Summary

Air pollution and smog started becoming serious problems in the 1940s, particularly in Los Angeles County, California. Once automobile exhaust was recognized as a major source of smog-producing emissions in the 1950s, L.A. County and then the State of California sought to establish laws regulating certain automotive emissions. These regulations later became the basis of U.S. federal emissions control rules. The early California program experienced many problems and was not as successful as hoped. To compensate, the standards became more stringent, and expanded to include other types of emissions.

Few things have had a greater influence on the design and engineering of modern automobiles than emissions control regulations. First initiated in California in the fifties and sixties, legislative and regulatory efforts to limit motor vehicle emissions soon became a model for U.S. federal standards, which in turn helped to shape environmental law in other countries. In this installment of Ate Up With Motor, we present a timeline of the major early events and developments in governmental control of auto emissions, from the 1940s through the end of the 1960s.

Introduction: Exploring a Smoggy Subject

We began this project out of frustration. Almost everyone who knows anything about American cars is aware that, beginning in the sixties, there was a major effort in California and then at the federal level to reduce harmful automotive emissions, including carbon monoxide, unburned hydrocarbons, and subsequently oxides of nitrogen, a response to growing problems of air pollution and photochemical smog. Japan and Australia followed the U.S. lead in the seventies, and Europe eventually followed suit. This effort led to many controversies, technological dead ends, and frustrations on all sides, from automotive journalists resentful of “smog-control” devices that sapped engine power to public health officials worried that emissions control efforts might prove too little, too late.

While these basics may be familiar to anyone interested in automotive history, finding specific information about the development, timing, and details of early emissions rules is surprisingly difficult. Environmental regulation is a subject of enormous global significance, so there is of course a voluminous amount of information about it — but, modern references are usually more concerned with current and proposed rules, not historical ones. If they mention the history at all, they will typically skim over everything prior to the landmark Clean Air Amendments of 1970 (Public Law 91–604, often called the Muskie Act, after the late Senator Edmund S. Muskie (D-Maine), its leading champion). At most, you might get a brief explanation of photochemical smog, a few references to chemist Arie Haagen-Smit (who was the first to establish the precursors and chemical mechanisms involved in the formation of smog), and a mention that California implemented its first automotive emissions standards in the 1960s. If you want more than that, you have to dig through old technical papers, ancient editions of the Federal Register, and 60- and 70-year-old press clippings, supplemented with a few older academic articles or books. A 2021 paper by S. Kent Hoekman and J. Steve Welstand in the journal Atmosphere, “Vehicle Emissions and Air Quality: The Early Years (19402–1950s)” (doi:10.3390/atmos12101354) offers a good overview of the early experimental work on vehicle emissions, but only through the latter fifties. A more broadly useful source was Pollution and Policy: A Case Essay on California and Federal Experience with Motor Vehicle Air Pollution, by James E. Krier and Edmund Ursin, originally published in 1977 and reissued in 2019, which covers this entire period, but even that excellent book lacks some of the information we wanted.

We were not satisfied with that, and began contemplating the idea of assembling a timeline of emissions control development, if only for our own reference (as would have been helpful for our early 2024 article on early electronic fuel injection). Given the enormous amount of work it would obviously involve, however, it seemed foolish not to approach it as something we could publish for the benefit of others.

What This Timeline Is (and What It Isn’t)

Our object for this timeline is to present major events in the development of governmental standards for automotive emissions (“smog control”) in chronological order. This timeline doesn’t by any means include every event, or even every important event, but we have sought to strike a balance between providing context and still presenting a comprehensible sequence of events.

Consequently, there are many details this timeline deliberately skims over: For instance, we have opted not to dwell on the mechanics of photochemical smog (which is amply covered elsewhere), the biographies of the key players, or the function of early emissions control devices like the Ford “Thermactor” air injection system, although we might return to some of those subjects later. The primary goal of this article is to provide a chronological framework for understanding the course of emissions regulation prior to 1970.

This timeline is primarily concerned with California and the U.S., because those are the jurisdictions where auto emissions laws first appeared. We have included some incidental references to other state laws and the early stirrings of emissions control in Japan, but for the most part, other countries did not adopt auto emissions laws until the seventies or later, and the emissions laws in other U.S. states were far less extensive or ambitious as the early California program. (We have not made a complete survey of all other state laws of the sixties, so we may have missed a few points that would have been worthy of inclusion.)

We also ignored laws focused on smoke or bothersome fumes or odors, which were adopted in many localities during this period. Anti-smoke laws are superficially similar to air quality standards and pollution controls, and they’ve often been adopted in response to pollution problems, but their focus is very different. Laws against excessive smoke or unpleasant odors are concerned with individual nuisance rather than collective environmental impact. One person illegally burning foul-smelling trash in their back yard is an annoyance that can be addressed with a citation or fine; a million people’s daily commuting dumping hundreds of tons of carbon monoxide and hydrocarbons into the air is a different, and much larger, social problem.

In the past, we have generally eschewed in-post footnotes or end notes for Ate Up With Motor articles, mostly because they are extremely cumbersome to manage in HTML. For this timeline, it seemed appropriate to include some, which is also why the article is not paginated as it customarily would be at this length, since the pagination would make the HTML end notes even more troublesome. Specific laws and regulations are cited inline in the text, and for federal laws and regulations, we have also included links to the original statutes or the regulations as they appeared in the Federal Register. (This is unfortunately difficult or impossible to do with older state and local regulations, or we would have included direct links to those as well.) A complete bibliography appears in “Notes on Sources,” per our usual practice.

Our hope is that this will be a worthwhile contribution to the general understanding of this very important subject, which auto enthusiasts and automotive historians (including us!) don’t necessarily grasp as well as we should.

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1940

According to the U.S. Public Roads Administration, there are about 32.0 million cars, trucks, and buses registered in the United States this year, 2.8 million (8.8 percent) of them in California. Los Angeles County has 1,160,124 registered cars and trucks, consuming almost 2 million gallons (7.5 million liters) of gasoline per day. Although no effort has yet been made to measure their exhaust emissions, these vehicles release an estimated 360 to 500 tons of unburned hydrocarbons, about 71 tons of oxides of nitrogen, and approximately 2,800 tons of carbon monoxide into L.A. County air every day.

1943

July

Los Angeles suffers its first really severe smog event, which chokes the downtown area so thoroughly that the dark, acrid haze is initially mistaken for a Japanese gas attack. Similar episodes become increasingly frequent occurrences in the Los Angeles area, particularly during the hot summer months, causing substantial eye and respiratory irritation and damaging plants and rubber goods such as tires.

1947

June

A new California law, the Air Pollution Control Act of 1947 (Ch. 632, § 1, [1947] Cal. Stats. Ex. Sess. 1640), establishes county-level air pollution control districts to regulate emissions from stationary sources (such as factories and incinerators), though not yet motor vehicles.

October

The Los Angeles County Board of Supervisors votes to establish the Los Angeles Air Pollution Control District (LAC APCD), which will become one of the earliest and most aggressive proponents of clean air regulation.

1949

Smog causes almost $480,000 in crop damage throughout Los Angeles County this year, although the chemical mechanism of the damage is still poorly understood. [1]

According to the U.S. Bureau of Public Roads, there are now almost 44.7 million cars, trucks, and buses registered in the United States — almost 4.2 million (9.3 percent) in California.

1950

Research by Arie Jan Haagen-Smit, Ph.D., a respected bio-organic chemistry professor at the California Institute of Technology (Caltech) in Pasadena, California, and a consultant for the LAC APCD, notes the connection between the chemical precursors of smog — hydrocarbons and oxides of nitrogen, which react in sunlight to form ozone and a brownish atmospheric haze with strong oxidizing properties — and the unburned hydrocarbons emitted by the many cars and trucks in Los Angeles County. [2]

Haagen-Smit’s hypothesis draws intense criticism from the Stanford Research Institute (SRI), which has been commissioned by the Western Oil and Gas Association Committee on Smoke and Fumes to study the smog issue. SRI downplays the severity of the problem and suggests that the chemical processes have too many contributing factors to blame on any “single class of violators.”

There are now 1,864,546 cars and trucks registered in Los Angeles County, consuming an estimated 3,460,000 gallons (13.1 million liters) of gasoline per day and producing an estimated 628 to 850 tons of unburned hydrocarbons, about 120 tons of oxides of nitrogen, and more than 4,500 tons of carbon monoxide per day.

1951

In Pasadena, California, SRI begins its own study of automotive tailpipe emissions, using an exhaust-sampling trailer to measure hydrocarbon emissions in actual driving.

1952

Arie Haagen-Smit publishes a more complete analysis of the chemical processes involved in photochemical smog. His work will become the foundation of many later efforts to control smog and smog-producing emissions. [3]

1953

February

Los Angeles County 2nd District Supervisor Kenneth F. Hahn begins writing to the presidents of the leading U.S. automakers, asking what can be done to address the automobile’s contribution to air pollution. The initial responses are generally dismissive. John M. Campbell, administrative director of the GM Engineering Staff, remarks, “As far as we are aware, Los Angeles is the only community having this particular complaint … indicating that perhaps some other factors than automobile exhaust gases may be contributing to this problem.” [4]

May

A paper by LAC APCD scientists estimates that gasoline engines in L.A. County are emitting an estimated 127 million cubic feet of carbon monoxide, 875 tons of unburned hydrocarbons, and 132 tons of oxides of nitrogen per day — increases of over 75 percent from 1940 levels. [5]

October

Supervisor Hahn requests a legal opinion from L.A. County Counsel Harold W. Kennedy on the possibility of requiring automobiles sold in Los Angeles County to be equipped with emissions control devices. Kennedy responds that until a “satisfactory device is perfected and available on the market,” such a requirement would be “arbitrary, capricious, and void.” Hahn continues writing frequently to the heads of major U.S. automakers to ask about the availability of such devices and urge their prompt development.

December

The Automobile Manufacturers Association (AMA) establishes a Vehicle Combustion Products subcommittee, chaired by John Campbell of GM, to study various aspects of automotive emissions and their contribution to air pollution.

1954

January

The AMA Vehicle Combustion Products subcommittee travels to Los Angeles to investigate the problems of smog there. For most of the committee members, the trip provides their first direct experience of the severity of photochemical smog, which (in the words of Chrysler engineers Charles M. Heinen and Walter S. Fagley Jr.) quickly makes them “believers” in a problem they have not previously taken very seriously. [6]

1955

January

At the annual meeting of the Society of Automotive Engineers (SAE) in Detroit, SRI scientists present the result of their exhaust emissions study, which essentially concedes that Arie Haagen-Smit’s analysis of the smog problem is correct. The study calls automobile exhaust “the largest single source of hydrocarbon pollutants to the Los Angeles atmosphere and also the most effective distribution system,” and proposes that automobiles be fitted with control devices that reduce hydrocarbon emissions by at least 60 percent in order to “return to the relatively smog-free years prior to 1945.” [7]

Later in the year, through the AMA, U.S. automakers establish a cross-licensing agreement that allows (and indeed requires) participating manufacturers and suppliers to share certain research and technology related to vehicle emissions control on a royalty-free basis.

July

U.S. President Dwight Eisenhower signs Senate Bill S. 928, the Air Pollution Control Act (Public Law 84–159), which authorizes $5 million a year for the Department of Health, Education, and Welfare (through the Public Health Service) to “provide research and technical assistance relating to air pollution control,” but leaves actual control and enforcement to state and local governments.

1956

April

The AMA Vehicle Combustion Products subcommittee establishes a Traffic Safety Panel to conduct an extensive survey of Los Angeles traffic patterns and how they correlate to engine operating characteristics such as manifold vacuum. This panel begins developing a standardized 11-mode driving test cycle to simulate typical L.A. traffic conditions for emissions testing purposes.

In an April 24 letter to L.A. County Supervisor Hahn, Ford Engineering VP Earle S. MacPherson notes that Ford is developing a deceleration fuel cutoff to reduce hydrocarbon emissions, and is tentatively willing to produce such devices if “both your air pollution control officer and ourselves are convinced that the devices will measurably reduce hydrocarbon emission.” A same-dated letter from Chrysler engineer Charles Heinen says that the answer to Hahn’s question about whether Chrysler intends to install emissions control devices on 1958 Chrysler models is “a very much qualified ‘yes.'”

May

In a May 1 letter to L.A. County Supervisor Hahn, GM Engineering Staff VP Charles A. Chayne says GM is “not in a position to offer a device on 1957 models for elimination of air pollution,” but adds that the corporation hopes by the end of 1956 “to have some prototype devices to offer the Los Angeles community for consideration.”

Los Angeles County air pollution control officer S. Smith Griswold tells reporters that air pollution and smog are fast becoming a global problem, noting that more than 100 U.S. cities have implemented public air pollution control programs. Griswold calls air pollution a “disease of the atmosphere caused by industrialization and growth.”

November–December

In Los Angeles, the Coordinating Research Council, Inc. (CRC) Field Survey Panel begins its Comprehensive Exhaust Gas Field Survey, measuring the automotive tailpipe emissions of 293 test cars in driving tests conducted on paved sections of the L.A. River, most using a 12-mode variation of the driving cycle suggested by the AMA Traffic Safety Panel.

1957

July

In a July 25 letter to L.A. County Supervisor Hahn, GM Engineering VP Charles Chayne says tests of a vacuum-limiting fuel cutoff to reduce hydrocarbon emissions have only achieved a “disappointingly small reduction,” but notes that GM has been exploring the possibility of reducing hydrocarbon and oxides of nitrogen emissions “by means of some type of afterburner or catalytic converter in the exhaust system.” Chayne cautions that “it is too soon to say whether this principle can be utilized in a practical way.”

August

At an SAE meeting in Seattle, the AMA Traffic Survey Panel presents the results of its traffic survey and its standardized test cycle. [8]

December

The CRC publishes the result of its Comprehensive Exhaust Gas Field Survey. This data provides a foundation for estimating the “baseline” emissions levels of contemporary passenger cars with no emissions controls. [9]

1958

April

In an April 7 letter to L.A. County Supervisor Hahn, Chrysler engineer Charles Heinen says Chrysler has continued working on exhaust afterburners, but that they “do not believe it is technically possible at present to establish a realistic deadline date for the installation of exhaust devices.”

In an April 9 letter to Supervisor Hahn, Ford engineer John M. Chandler points out that the LAC APCD has evaluated experimental deceleration fuel cutoff devices and concluded that they reduce hydrocarbon emissions by less than 25 percent, which district officials do not is feel worth the cost. Chandler adds that Ford has continued work on catalytic afterburners.

In an April 15 letter to Supervisor Hahn, GM VP Charles Chayne notes that GM experimental catalytic converters and afterburners have not yet reached a “commercially acceptable” stage and asserts that “the solution cannot be ordered by legislation.”

October

During a legislative hearing in Sacramento, California, L.A. County officials call for state action to limit motor vehicle exhaust emissions.

1959

January–February

California Assemblymember Thomas M. Rees (D-Los Angeles) and Senator Richard Richards (D-Los Angeles) introduce the Rees-Richards Act (Calif. Senate Bill No. 117 and Assembly Bill No. 1368), which orders the California Department of Public Health to set state air quality standards and then establish, no later than February 1, 1960, “maximum allowable standards of exhaust contaminants from motor vehicles which are compatible with the preservation of the public health.” Although the requested motor vehicle exhaust standards will not yet have the force of law, they are intended as the basis for subsequent legislation to limit tailpipe emissions from automobiles in California.

In a January 19 letter to L.A. County Supervisor Hahn, GM president John F. Gordon notes engineering development programs for a catalytic exhaust control device invented by Eugene J. Houdy now “appear feasible,” and recommends that Los Angeles County develop “an effective system of vehicle inspection” to ensure the proper function of any installed smog devices. However, Gordon is quick to insist that research studies “thus far have failed to show any unmistakable effects on health [from auto exhaust] — and thus there is no cause for immediate alarm even in Los Angeles.”

April

California Governor Edmund G. (Pat) Brown signs the Rees-Richard Act (Ch. 200, § 1. Ch. 835, § 1. [1959] Cal. Stats. Reg. Sess. 2091, 2885). The new law declares, “The pollution of the air by the discharge of air pollutants from the exhausts of motor vehicles constitutes one of the most serious threats to the heath of the people of this State. It is imperative that standards for the discharge of such pollutants be developed without delay.”

November

The AMA announces that by the start of the 1961 model year, U.S. automakers will voluntarily fit all new cars and light trucks sold in California with positive crankcase ventilation (PCV) systems that return crankcase “blowby” (air-fuel mixture forced past the piston rings) to the engine to be burned, rather than discharging it to the atmosphere through a road draft tube.

December

The California Department of Public Health finalizes its initial automobile tailpipe exhaust standards: hydrocarbon (HC) emissions no greater than 275 parts per million (ppm) by volume as hexane, and carbon monoxide (CO) emissions no greater than 1.5 percent by volume. These limits represent a decrease of 80 percent in HC emissions and 60 percent in CO emissions from an estimated baseline of 1,375 ppm HC and 3.8 percent CO for cars with no emissions controls, calculated based on data from the CRC Comprehensive Exhaust Gas Field Survey. Although CDPH acknowledges the role of oxides of nitrogen (NOx) in creating smog, they decline to set NOx limits at this time, citing insufficient data; they acknowledge that tailpipe NOx limits may be required later. Crankcase and evaporative emissions are also omitted. The standards call for compliance with the HC and CO limits to be measured using an 11-mode driving cycle modeled on the one previously developed by the AMA Traffic Survey Panel. [10]

As of December 31, 1959, California Department of Motor Vehicles (DMV) data indicates that California has 7,300,028 registered cars and trucks (2,930,006 of those in Los Angeles County) — a 75 percent increase from 1949, and almost 10 percent of the 73.9 million cars and trucks registered in the United States.

1960

January

At the SAE Annual Meeting in Detroit, engineers from the GM Research Laboratories present research claiming that crankcase emissions of engine blowby released through the road draft tube comprise a much greater percentage of a vehicle’s total hydrocarbon emissions than previously assumed — perhaps as much as 40 percent, although the paper admits that actual emissions vary considerably between individual vehicles and are difficult to accurately measure. [11]

The Los Angeles County Air Pollution Control District estimates that motor vehicles now produce more than two-thirds of hydrocarbon emissions, 61 percent of NOx emissions, and 91 percent of all CO emissions in L.A. County, undermining progress made in controlling emissions from stationary sources.

March–April

During its first extraordinary session of 1960, the California Legislature introduces and passes the Motor Vehicle Pollution Control Act (Assembly Bill No. 17), which Governor Brown signs on April 28 (Ch. 23. § 1, [1960] Cal. Stats. 1st Ex. Sess. 346). This law calls for the creation of a state Motor Vehicle Pollution Control Board (MVPCB) that will be responsible for certifying emissions control devices to enable cars sold in California to comply with the state’s CO and HC standards. Compliance will not be required until one year after the MVPCB approves at least two suitable devices. Once two such devices are certified, the state intends to prohibit most new and some used cars from being registered with the California DMV unless they have a certified device or the MVPCB has issued an exemption. Individual counties not located in an air pollution control district can opt out of the used-car requirement for vehicles registered there. Diesel engines and trucks larger than one-half ton rating are exempt for now.

May

Although the auto industry’s voluntary introduction of positive crankcase ventilation systems for California cars draws praise from state officials, William L. Faith, Ph.D., managing director of the nonprofit Air Pollution Foundation, is unimpressed, noting that crankcase vapors represent a much smaller percentage of total motor vehicle emissions than does engine exhaust.

July

California’s 13-member Motor Vehicle Pollution Control Board begins operations.

October

In an October 25 letter to L.A. County Supervisor Hahn, Ford engineer John M. Chandler notes that an experimental Ford catalytic converter has been “eliminated from consideration” because it only reduces hydrocarbon emissions, not carbon monoxide.

December

The California Department of Public Health adds crankcase emissions standards to the existing 1959 California CO and HC standards: no more than 0.15 percent by weight of the supplied fuel (compared to an estimated 2 percent by weight for uncontrolled crankcase emissions).

An Assembly subcommittee report notes that smog is now a problem in 25 of California’s 58 counties, causing about $8 million in crop damage a year for California agriculture. The ongoing problem of crop damage helps to create strong bipartisan support for emissions control measures; California farmers are paying a heavy price for big-city pollution.

1961

January

In its first biennial report to the governor and the Legislature, the California Motor Vehicle Pollution Control Board remarks, “The ideal solution to the problem [of smog control] would, of course, be the control of motor vehicle exhaust emissions by engine design changes. … Yet because of the urgency of solving the present air pollution problem, it is not feasible to delay a control program until such time as engine design has progressed to the stage where it alone can control these emissions.”

The MVPCB begins testing crankcase emissions devices. Due to limited resources, the board’s certification testing seeks only to confirm test data submitted by device manufacturers. The board establishes regulations requiring approved devices “to operate efficiently for at least 12,000 miles [19,300 km] with normal maintenance.” (Cal. Admin. Code, tit. 13, § 2003 et seq.)

May

The MVPCB approves standardized testing procedures for measuring CO and HC emissions. As the California Department of Public Health standards specify, the procedure is based on the 11-mode driving cycle developed by the AMA Traffic Survey Panel, but is performed on a chassis dynamometer rather than a test track, and adds an additional seven-model cycle (repeated six times prior to the 11-mode cycle) to better simulate the greater emissions an engine produces during warm-up; final test results are a weighted average of these cycles. [12]

December

The AMA announces that U.S. automakers will voluntarily equip all U.S.-market new cars and trucks with PCV systems, beginning with the 1963 model year.

1962

April

The California MVPCB certifies five crankcase emissions control devices for factory installation. Only one is certified for engines under 140 cu. in. (2,294 cc) displacement, although Volkswagen receives certification for its own device, since the air-cooled VW engine falls into a special “unusual engine design” category.

June

As directed by the federal Schenck Act (Public Law 86–493), the U.S. surgeon general submits to Congress a three-volume, 460-page report entitled Motor Vehicles, Air Pollution, and Health, summarizing current research on the different aspects of automotive contributions to air pollution, as well as the current California emissions control program. Congress responds by authorizing additional research.

July

In a July 9 letter to GM president Jack Gordon, L.A. County Supervisor Hahn expresses his growing frustration and disappointment at “the automobile’s failure to accept its responsibility” in reducing pollution. Hahn adds, “unless this is done promptly, it might be necessary for the Congress of the United States to pass such necessary laws as would require the industry to equip its products with equipment that will lessen the amount of pollution emitted into the atmosphere.” In his reply dated July 18, Gordon notes that the California MVPCB “has as yet not found it possible to approve any device for control of exhaust gases,” and points out again the lack of “an effective system of vehicle inspection” for emissions control devices.

December

California’s MVPCB approves its 15th and 16th crankcase emissions control devices for factory installation, and affirms that a certified device will be required on most 1964 new cars and trucks sold in California (although by this time most models already have them). The board also approves two devices deemed suitable for retrofitting to most used cars, and announces that starting January 1, 1964, most 1950–1960 used cars and trucks must be fitted with a certified PCV device prior to any sale or title transfer, with mandatory retrofit to be required for most privately owned vehicles (even with no title transfer) beginning January 1, 1965.

1963

As Japanese automakers prepare crankcase emissions devices to comply with new state requirements in the U.S., the Japanese Ministry of Health and Welfare asks automakers to also work on lowering the emissions of their domestic products. The automobile industry association insists that there is no evidence that auto emissions cause health problems.

March

The New York State Department of Health Air Pollution Control Board adopts a resolution that requires crankcase devices to reduce blowby emissions by at least 80 percent on all motor vehicles manufactured after June 1963 that are registered in New York.

July

California Governor Brown approves a new state law (Ch. 2028, § 1, [1963] Cal. Stats. Reg. Sess. 4169) allowing individual counties to implement emissions control inspection programs — and requiring motorists to affirm under penalty of perjury that any vehicle they register with the DMV has any required certified emissions control devices. The law also requires state licensing for smog device installation, inspection, or repair providers, and prohibits tampering with certified smog-control devices, or operating a vehicle without one where required.

December

U.S. President Lyndon Johnson signs House Bill H.R. 6518, the Clean Air Act of 1963 (Public Law 88–206), which for the first time gives the federal government some statutory authority to investigate and order abatement of air pollution problems that endanger health and welfare. The law also calls for the establishment of federal air quality criteria, although the government’s practical ability to enforce any actual standards (or demand abatement) remains very limited.

1964

January

California’s MVPCB approves revised testing procedures for HC and CO emissions, now based exclusively on the seven-mode cycle rather than the original AMA-recommended 11-mode one. Later in the year, the MVPCB and the California Department of Public Health develop a new seven-mode test cycle intended to represent morning rush hour traffic along a Los Angeles street route known as LA4, rather than the 24-hour driving average represented by the AMA Traffic Survey Panel cycle. [13]

February

A joint resolution of the Colorado Legislature requires PCV devices on new U.S.-built gasoline-powered cars and trucks beginning with the 1965 model year (Col. House Joint Res. 1022).

At some time during the 1964 model year, and extending into 1965, Ford Motor Company drops its positive crankcase ventilation system and reverts to a road draft tube, except on the Ford Thunderbird, Lincoln Continental, and cars bound for states where crankcase emissions controls are now required by law.

June

The California MVPCB approves four exhaust emissions control devices suitable for factory installation on new cars. This triggers the state’s statutory mandate, meaning that most new cars sold in California will be required to have a certified exhaust device (as well as a certified crankcase device) beginning in the 1966 model year. None of the four approved devices — catalytic converters developed by Arvin Industries Universal Oil Products, Walker Manufacturing Company—American Cyanamid, and Norris Thermador—W.R. Grace & Co. and an afterburner developed by American Machine and Foundry Co. under license from Chromalloy Corporation — is ever adopted for new cars, with automakers instead preferring to develop their own systems or use technology available to them royalty-free under the AMA cross-licensing agreement.

August

At a California MVPCB meeting, American Motors, Chrysler, Ford, and General Motors announce that they will equip most (though not all, due to claimed tooling and supply limitations) of their 1966 California cars with exhaust control devices. The AMC Air-Guard, Ford Thermactor, and GM Air Injection Reactor all use air pumps to inject fresh air into the exhaust manifold, combusting unburned hydrocarbons and carbon monoxide to produce carbon dioxide. The Chrysler “Cleaner Air Package” (CAP) instead uses a set of carburetor mixture and spark advance modifications that reduce CO and HC emissions without additional equipment, although because it requires the engine to be kept in proper tune, it will demand more maintenance than air injection systems. International Harvester and Kaiser Jeep subsequently indicate that they too will use air injection systems in California.

October

California’s Department of Public Health adopts more stringent California standards that will become effective for 1970: hydrocarbon emissions of no more than 180 ppm; CO emissions of no more than 1.0 percent by volume; and evaporative emissions no greater than 2 grams per soak for carburetor losses and no more than 6 grams per day for fuel tank evaporative losses. The limit for crankcase emissions is also reduced, to 0.1 percent of supplied fuel.

December

California’s “pink slip” crisis begins: The Department of Motor Vehicles sends out 1965 registration renewal notices with a confusingly worded pink insert intended to explain the new crankcase device requirements. This nearly incomprehensible document, which demands an affidavit under penalty of perjury, causes an immediate public backlash, convincing Governor Brown and the Legislature that the mandatory retrofit program for used cars should be limited to title transfers — and that the law should be promptly amended so that failure to comply, or a mistake on the registration forms, will not constitute a crime.

1965

January

At the urging of Supervisor Kenneth Hahn, the Los Angeles County Board of Supervisors calls on the U.S. attorney general to investigate the auto industry for “possible conspiracy and unfair competition … in the design, production, and distribution of automobile smog control devices.”

March

Ford resumes installing PCV systems on all models, now using the improved “jiggle-pin” valve system already used on the 1964–1965 Thunderbird and Lincoln Continental. Most domestic makes now use similar systems to reduce maintenance headaches due to clogged PCV valves.

July

California Governor Brown approves a revised motor vehicle emissions law (Ch. 2031, § 1, [1965] Cal. Stats. Reg. Sess. 4606), which is intended to speed up the adoption of emissions control devices. It halts the “pink slip” program for privately owned used vehicles, but still requires most used cars as old as 1955 to be retrofitted with exhaust and crankcase devices before sale or transfer of title, with the as-installed cost limited by statute to no more than $65. The law also extends the crankcase and exhaust emissions standards to include larger gasoline-powered trucks and buses, beginning with the 1969 model year, while sharply limiting the ability of the MVPCB to grant exemptions. This means that imported cars with engines smaller than 140 cu. in. (2,294 cc) must comply with California exhaust standards starting in 1968, although they are still exempt from the 1966–1967 requirement. Vehicle registration fees are increased to pay for a massive expansion of the California Highway Patrol, which is empowered to conduct random roadside inspections for compliance with the emissions control device rules.

October

President Johnson approves Senate Bill S. 306, the Motor Vehicle Air Pollution Control Act (Public Law 89–272), which directs the secretary of the U.S. Department of Health, Education, and Welfare (HEW) to establish emissions standards for new motor vehicles and new motor vehicle engines, and prohibits the importation or sale of new vehicles or engines that don’t comply with the standards. It isn’t yet clear whether the federal law will completely preempt state emissions standards (although that appears to be the legislative intent) or whether states will be permitted to set their own stricter standards.

In California, the Department of Public Health amends the state’s motor vehicle exhaust standards to add a limit of 350 parts per million oxides of nitrogen (NOx), which will become effective for passenger cars for the 1970 model year.

1966

January

Los Angeles County Supervisor Hahn again asks the U.S. attorney general to investigate the auto industry for collusion in allegedly delaying the availability of emissions control devices.

In the January 1966 issue of Car Life, automotive writer Wayne Thoms admits, “I’d like to be able to state a valid case that would free the automobile from the bulk of the blame for smog. But I cannot. If some monstrous conspiracy is concealing the facts that would lay the blame elsewhere, it has been totally effective.”

March

The California Highway Patrol makes it departmental policy to inspect a vehicle’s emissions devices on most traffic stops.

In the the Federal Register for March 30, 1966, HEW publishes the first U.S. federal exhaust emissions standards for new motor vehicles and engines, effective for the 1968 model year. Motorcycles, commercial vehicles over one-half ton, and diesel engines are exempt. Unlike the California standards, the federal exhaust emissions standards differ depending on engine displacement:

• Under 50 cu. in. [820 cc]: Exempt
• Between 50 and 100 cu. in. [820 and 1,640 cc]: 410 ppm hydrocarbons and 2.3 percent carbon monoxide
• Between 100 and 140 cu. in. (1,640 cc and 2,294 cc): 350 ppm HC and 2.0 percent CO
• Engines greater than 140 cu. in. (2,294 cc): 275 ppm HC and 1.5 percent CO

NOx and evaporative emissions are excluded, but unlike California and New York, the federal crankcase standards require that crankcase emissions be completely eliminated rather than just greatly reduced.

April

In Japan, the Ministry of Transportation imposes a limit of 3.0 percent carbon monoxide by volume for all newly designed gasoline-engine passenger cars, trucks, and buses for the Japanese domestic market (JDM), effective September 1966, and requires that existing JDM production models receive similar controls by fall 1967. Compliance will be measured using a new four-mode test cycle.

June

In Detroit, Automotive News engineering editor Joseph M. Callahan launches a series of more than 30 articles characterizing automotive emissions controls as a “billion-dollar hoax,” claiming that Los Angeles smog is unrepresentative of the rest of the country and that the attack on the auto industry is unwarranted and unfair.

July

The U.S. Department of Justice begins a federal grand jury investigation of whether automakers have engaged in conspiracy and unfair competition in the development of emissions control devices.

August

The California Department of Public Health revises the state’s standards for motor vehicle exhaust hydrocarbons and carbon monoxide to conform with the new federal regulations, with more generous standards for engines smaller than 140 cu. in. (2,294 cu. in.). The stricter state standards previously set for 1970 (which will apply to all vehicles regardless of engine size) remain as before.

September

Speaking at an air pollution conference in Geneva, Eric P. Grant, executive director of the California MVPCB, warns European automakers that they will have to comply with U.S. emissions rules starting with the 1968 model year.

November

The Los Angeles County Air Pollution Control District presents a report to the board of supervisors revealing that in MVPCB tests of 532 1966 vehicles equipped with exhaust emissions control devices, more than half exceeded the state HC and/or CO limits. The likelihood that a given vehicle would be over the limits appeared to increase substantially with greater mileage; the APCD report predicts that “at 50,000 miles essentially all of the vehicles will fail to meet the State standards.” Tests also found that emissions of oxides of nitrogen — a major component of photochemical smog, though not yet regulated — had greatly increased compared to earlier models without exhaust devices. L.A. County air pollution control officer Louis J. Fuller warns that the modest reductions in hydrocarbon emissions “will make no discernible difference in smog, and even these reductions may be offset by the increases in oxides of nitrogen.” Automakers blame the problem on poor maintenance.

In New York, a severe smog event around Thanksgiving causes an estimated 80 deaths throughout the Greater New York area.

1967

Midway through the 1967 model year, some automakers, beginning with AMC, switch from air injection to the cheaper and less complex Chrysler Cleaner Air Package, which is available on a royalty-free basis for signatories of the 1955 AMA cross-licensing agreement.

February

Outraged by the LAC APCD report on the failures of exhaust control devices, L.A. County supervisor Kenneth Hahn calls the program a failure, declaring that “the motoring public has paid $47 million for potential junk” and demanding a massive recall of 1966 California cars to repair and upgrade their exhaust controls. MVPCB executive director Eric P. Grant rejects that idea and rationalizes the failures by arguing that on average, the 1966 cars “come very close to meeting state standards,” and are still substantially reducing HC and CO emissions. The MVPCB’s “averaging” strategy — accepting that some cars will exceed the emissions limits for at least part of their useful lives as long as the overall averages are at or close to the standards — continues to draw fire from the press and L.A. County officials, prompting defensive reactions from the MVPCB.

Joe Callahan brings his “Billion-Dollar Smog Hoax” crusade to the March 1967 issue of Motor Trend, proclaiming that the automobile engine “may be legislated out of existence in one of history’s worst miscarriages of justice,” and announcing that he has been called to testify about the problem before a Senate subcommittee. Callahan’s “smog hoax” campaign helps to galvanize “buff book” hostility toward regulation of auto emissions.

During the testimony of L.A. County air pollution control officer Louis Fuller before the Senate subcommittee on air and water pollution on February 13, senators express doubts about the effectiveness of engine modification packages such as the Chrysler Cleaner Air Package compared to air injection or catalyst systems. Senator George Murphy (R-Calif.) remarks, “it would seem that we have gone back to something that is a very obvious, makeshift substitute which doesn’t do the job, the Cleaner Air Package.” In his testimony later in the day, California MVPCB executive director Eric Grant acknowledges that the addition of CO and HC exhaust controls on California cars has increased NOx emissions by about 10 percent, but says the board has revised its certification rules to require that CO and HC controls not increase NOx emissions by more than 15 percent.

In a subsequent subcommittee hearing in Detroit on February 20, General Motors Engineering Staff vice president Harry F. Barr tells senators, “I don’t know what you were told about oxides of nitrogen in California, but we are not convinced that we have evidence that this is really serious as a health problem as some have indicated.” Barr concedes that even with the more stringent proposed emissions, the growth of the U.S. car population means that total hydrocarbon emissions will likely begin to rise again by the 1980s, even with crankcase, exhaust, and evaporative controls. In his separate testimony later that day, Joe Callahan, echoing the smog deniers of 15 years earlier, says that based on his interviews with scientists, officials, and industry experts, he remains convinced that “The small quantities of unburned hydrocarbons which come from a car are invisible and they cause no problems, except when they are contained in an enclosed area.” [15]

May

Toyota becomes the first Japanese automaker to receive California certification for its 1968 emissions controls.

July

A motor vehicle pollution status report from the California Department of Public Health estimates that by 1970, hydrocarbon emissions in Los Angeles and other major California urban areas will only only be rolled back to 1957 levels, not the 1940 levels that were the original target — the growing number of cars on the road still threatens to outpace reductions in automotive emissions. The report also notes that the auto industry’s rejection of emissions control technology developed by independent companies “has removed much of the stimulus for further device development by automobile manufacturers.” [16]

On July 12, the California MVPCB certifies the 1968 emissions controls of 13 automakers: American Motors, Chrysler, Ford, General Motors, International Harvester, Daimler-Benz, Isuzu, Nissan, Peugeot, Porsche, Saab, and Volvo. (Isuzu has not previously sold cars in the U.S., but intends to enter the U.S. market shortly.)

August

New California Governor Ronald Reagan signs Senate Bill No. 490, the Mulford-Carrell Air Resources Act (Ch. 1545, § 1, [1967] Cal. Stats. Reg. Sess. 3679), which establishes a new California Air Resources Board (CARB) with authority to set and enforce air quality standards for each of the state’s various air basins. The politically embattled Motor Vehicle Pollution Control Board is abolished and its powers and responsibilities are transferred to CARB, as is most of the former role of the Department of Public Health Bureau of Air Sanitation in setting air quality and emissions standards.

October

A federal grand jury returns its findings on the auto industry smog collusion investigation, but the Department of Justice does not immediately take action.

November

President Johnson signs the Air Quality Act of 1967 (Public Law 90–148), which clarifies that federal emissions standards for new motor vehicles or engines completely preempt state rules except for California’s. Under the new law, California (and only California) may receive a waiver of preemption unless the secretary of Health, Education, and Welfare determines that the state “does not require standards more stringent than applicable Federal standards to meet compelling and extraordinary conditions” or that its enforcement procedures are not otherwise consistent with the federal law. Other states can still set their own emissions rules for used cars, but not new ones.

December

California Governor Reagan appoints Los Angeles County pollution control officer Louis Fuller as chairman of the California Air Resources Board.

1968

March

Louis Fuller resigns as California Air Resources Board chairman, citing conflicts of interest with his role in Los Angeles. Governor Reagan appoints Arie Haagen-Smit, previously a member of the MVPCB, to succeed him as chairman.

April

CARB informs automakers that new cars sold in California will be required to have evaporative emissions controls beginning with the 1970 model year.

June

In the Federal Register for June 4, 1968, HEW finalizes updated federal emissions rules that limit fuel system evaporative losses to no more than 6 grams per test, beginning with the 1971 model year for passenger cars and 1972 for off-road utility vehicles. The revised regulations also redefine the federal hydrocarbon and carbon monoxide standards for passenger cars and light trucks based on total emissions mass per vehicle mile rather than as percentage of exhaust volume: no more than 2.2 grams per vehicle mile HC and 23 grams per vehicle mile CO, starting with the 1970 model year. (The limits for gasoline-powered heavy-duty vehicles (trucks and buses with a gross vehicle weight rating of more than 6,000 lb (2,724 kg)) are still set at 275 ppm hydrocarbons and 1.5 percent carbon monoxide by volume.)

July

California Governor Reagan signs Assembly Bill No. 357, the Pure Air Act of 1968 (Ch. 764, § 1, [1968] Cal. Stats. Reg. Sess. 1463), which (among other things), for the first time specifies statutory emissions standards rather than leaving them to be set by regulation or established by the Department of Public Health, although CARB is authorized to set more stringent standards where it deems “necessary and technologically feasible.” The previously established 1970 standard for oxides of nitrogen is deferred for an additional year. Exhaust standards for passenger cars and light trucks for 1970 and later model years are restated in grams per vehicle mile:

• 1970: 2.2 g/mile HC, 23 g/mile CO; NOx not yet regulated
• 1971: 2.2 g/mile HC, 23 g/mile CO, 4.0 g/mi NOx
• 1972–1973: 1.5 g/mile HC, 23 g/mile CO, 3.0 g/mile NOx
• 1974 and later: 1.5 g/mile HC, 23 g/mile CO, 1.3 g/mile NOx

Evaporative emissions standards are still set to take effect for 1970, but are restated as 6 grams per test. The Pure Air Act also calls for emissions standards to be extended to diesel engines, which have previously been exempt.

1969

January

More than a year after the completion of the grand jury investigation, the U.S. Department of Justice Antitrust Division files a Sherman Antitrust Act suit against American Motors, Chrysler, Ford, GM, the AMA, Checker, Diamond T, International Harvester, Kaiser Jeep, Mack Trucks, Studebaker Corporation, and White Motor Corporation, charging that they have unlawfully conspired to ensure that none of the signatories of the 1955 AMA cross-licensing agreement would offer automotive emissions control devices prior to certain prearranged dates, and to attempt to delay the introduction of exhaust control devices in California.

April

The U.S. Department of Health, Education, and Welfare issues a draft of a new procedure for exhaust emissions testing, more accurately measuring true emissions mass using a new constant volume sampler (CVS) technique. [17]

May

HEW grants California a waiver of federal preemption under the Air Quality Act of 1967, which allows the state to impose its own, more stringent motor vehicle emissions standards. CARB chairman Haagen-Smit emphasizes that the state will no longer allow averaging across test groups during certification (which the federal standards still do) and will require every vehicle in every test group to comply with the California standards before the model can be certified for sale in the state.

September

The County of Los Angeles sues leading automakers for $100 million for obstruction of the county’s pollution control efforts. Six days later, on September 11, the U.S. Department of Justice announces that it has accepted a consent decree in the federal antitrust lawsuit, with the defendants promising not to engage in any conspiracy to obstruct emissions controls, but not admitting to any prior wrongdoing. L.A. County Supervisor Kenneth Hahn declares that Los Angeles residents have been “sold down the river” by the DOJ, while the California attorney general and city officials throughout the country file formal objections to the consent agreement.

October

Despite public and political outcry, including protests outside the courthouse, District Court Judge Jesse W. Curtis Jr. swiftly approves the consent decree in the auto industry antitrust case, saying that smog “is simply not a problem the courts can deal with.” Curtis also orders records of the grand jury investigation sealed, preventing other litigants from accessing the evidence the grand jury had gathered. The U.S. Supreme Court later upholds Curtis’s ruling (on March 16, 1970) and subsequently dismisses a raft of related state lawsuits against the auto industry. [18]

November

HEW abandons the seven-mode emissions test cycle and instead records data from actual urban driving to create a new standardized test schedule, known as the Federal Urban Dynamometer Driving Schedule (UDDS). [19]

At an Environmental Quality Council meeting on November 20, auto industry leaders indicate that stricter federal exhaust emissions standards proposed for the 1975 model year are technically feasible, although they want the current standards to remain unchanged until then rather than having tougher standards phased in over the next four years.

The U.S. Department of Transportation Federal Highway Administration estimates that the total number of cars and trucks on the road in the United States is now almost 109 million, up more than 47 percent from 1959. Twelve million motor vehicles are now registered in California — about 3.8 million of those in Los Angeles County.

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End Notes

1. John T. Middleton, J.B. Kendrick Jr., and H.W. Schwalm, “Smog in the South Coastal Area,” California Agriculture (Hilgardia) Vol. 4, No. 11 (November 1950): 7–10. doi:10.3733/ca.v004n11p7
2. A.J. Haagen-Smit, “The Air Pollution Problem in Los Angeles,” Caltech Engineering and Science Vol. 14, No. 3 (December 1950): 7–13. https://resolver.caltech.edu/CaltechES:14.3.air
3. A.J. Haagen-Smit, “Chemistry and Physiology of Los Angeles Smog,” Industrial and Engineering Chemistry Vol. 44, No. 6 (June 1952): 1342–1346. doi:10.1021/ie50510a045
4. Kenneth Hahn, Supervisor, Second District, County of Los Angeles Board of Supervisors, A Factual Record of Correspondence Between Kenneth Hahn, Los Angeles County Supervisor, and the Presidents of General Motors, Ford, and Chrysler Regarding the Automobile Industry’s Obligation to Meet Its Rightful Responsibility in Controlling Air Pollution from Automobiles, February, 1963–January 1967 (Los Angeles: County of Los Angeles, 1967). Subsequent quotes from Hahn’s correspondence are from the same edition, which was entered into the record during hearings of the U.S. Senate Subcommittee on Air and Water Pollution in February 1967.
5. Gordon P. Larson, George I. Fischer, and Walter J. Hamming, “Evaluating Sources of Air Pollution,” Industrial & Engineering Chemistry Vol. 45, No. 5 (May 1953): 1070–1074. doi:10.1021/ie50521a055 (See also reference 14 below.)
6. Charles M. Heinen and Walter S. Falgey Jr., “Smog – The Learning Years–Building the 88th Story,” SAE Technical Paper 890813 (Warrendale, Pa.: Society of Automotive Engineers, Inc., 1989); doi:10.4271/890813
7. Dale H. Hutchison and Francis R. Holden, Stanford Research Institute, “An Inventory of Automobile Gases,” Journal of the Air Pollution Control Association Vol. 5, No. 2 (August 1955): 71–74, 118. doi:10.1080/00966665.1955.10467691
8. D.M. Teague et al, “Los Angeles Traffic Pattern Survey,” Paper No. 171, Proceedings of the SAE National West Coast Meeting (New York: Society of Automotive Engineers, Inc., 1957), reprinted in Vehicle Emissions (Selected SAE Papers Vol. 6) (1964): 17–38.
9. Coordinating Fuel and Equipment Research Committee of the Coordinating Research Council, Comprehensive Exhaust Gas Field Survey, Los Angeles, November—December, 1956 (New York: Coordinating Research Council, Inc., 1957).
10. John A. Maga and Gerhardt C. Hass, “The Development of Motor Vehicle Exhaust Emission Standards in California,” Journal of the Air Pollution Control Association, Vol. 10, No. 5 (May 1960): 393-414. doi:10.1080/00022470.1960.10467949
11. P.A. Bennett, C.K. Murphy, M.W. Jackson, and R.A. Randall, “Reduction of Air Pollution by Control of Emission from Automotive Crankcases,” SAE Transactions Vol. 68 (1960): 514–536.
12. Gerhardt G. Hass and Miles L. Brubacher, “A Test Procedure for Motor Vehicle Exhaust Emissions,” Journal of the Air Pollution Control Association Vol. 12, No. 11 (November 1962): 505–543. doi:10.1080/00022470.1962.10468120
13. Gerhardt C. Hass, M. P. Sweeney, and J. N. Pattison, “Laboratory Simulation of Driving Conditions in the Los Angeles Area,” SAE Technical Paper 660546 (New York: Society of Automotive Engineers, Inc., 1966). doi:10.4271/660546
14. State of California, Department of Public Health, Technical Report of California Standards for Ambient Air Quality and Motor Vehicle Exhaust (Berkeley, Calif.: California Department of Public Health, 1960).
15. United States Senate, Ninetieth Congress, Air Pollution—1967 (Automotive Air Pollution): Hearings Before the Subcommittee on Air and Water Pollution of the Committee on Public Works, United States Senate, Ninetieth Congress, First Session on Problems and Progress Associated With Control of Automobile Exhaust Emissions, Part 1 (Washington, D.C.: U.S. Government Printing Office, 1967).
16. John A. Maga, Harmon Wong-Woo, and Milton G. Mason, “A Status Report on Motor Vehicle Pollution in California,” Journal of the Air Pollution Control Association Vol. 17, No. 7 (July 1967): 435–438. doi:10.1080/00022470.1967.10469001
17. Stanley H. Mick and John B. Clark, Jr., GM Engineering Staff, “Weighing Automotive Exhaust Emissions,” SAE Technical Paper 690523 (New York: Society of Automotive Engineers, Inc., 1969). doi:10.4271/690523
18. Scott H. Dewey, “‘The Antitrust Case of the Century’: Kenneth F. Hahn and the Fight Against Smog,” Southern California Quarterly Vol. 81, No. 3 (Fall 1999): 341–376. Available at SSRN: https://ssrn.com/abstract=1762770
19. Ronald E. Kruse and Thomas A. Huls, Environmental Protection Agency, “Development of the Federal Urban Driving Schedule,” SAE Technical Paper 730553 (New York: Society of Automotive Engineers, Inc., 1973). doi:10.4271/730553

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NOTES ON SOURCES

In addition to the bills and statutes cited in the text, our sources included Associated Press, “Anti-Smog Bill Passes; Measure Calls for Devices on Cars in California,” Reading Eagle [Reading, Calif.] 6 April 1960: 49; “Haagen-Smit Named Head of Air Board,” Los Angeles Times 8 March 1968: A8; and “Smog Device to Be Added to New Cars,” Lakeland Ledger [Lakeland, Fla.] 2 May 1960: 19; Thomas C. Austin, Robert H. Cross and Patty Heinen, California Air Resources Board, “The California Vehicle Emission Control Program — Past, Present and Future,” SAE Transactions Vol. 90 (1981): 3824–3872; “Automakers Face New Task in Smog Control; Action of State Health Board Seen as Complicating Problem of Car Exhaust,” Los Angeles Times 29 October 1964: 22; Automobile Manufacturers Association, Automobile Facts and Figures, various, 1940–1971; E. W. Beckman, Walter S. Fagley, and Jorma O. Sarto, Chrysler Corporation, “Exhaust Emission Control by Chrysler—The Cleaner Air Package,” SAE Technical Paper 660107 (New York: Society of Automotive Engineers, Inc., 1966); P.A. Bennett, C.K. Murphy, M.W. Jackson, and R.A. Randall, “Reduction of Air Pollution by Control of Emission from Automotive Crankcases,” SAE Transactions Vol. 68 (1960): 514–536; Joseph M. Callahan, “The Billion-Dollar Smog Hoax!” Motor Trend Vol. 19, No. 3 (March 1967): 68–70; California Legislature, Assembly Interim Committee on Public Health, Motor Vehicle Created Air Pollution: A Control Program for California (Sacramento, Calif.: Assembly of the State of California, December 1960); “California Moves to Cut Car Fumes; Makes Anti-Smog Devices Compulsory Next Year,” New York Times 18 June 1964: 35; “Car Smog Devices Cleared on Coast; Plans of 8 Foreign Makers Included for First Time,” New York Times 13 July 1967: 30; John M. Chandler, J.M. Struck, and W.J. Voorhies, Ford Motor Company, “The Ford Approach to Exhaust Emission Control,” SAE Technical Paper 660163 (New York: Society of Automotive Engineers, Inc., 1966); Diana Clarkson and John T. Middleton, California Motor Vehicle Pollution Control Board, “The California Control Program for Motor Vehicle Created Air Pollution,” Journal of the Air Pollution Control Association Vol. 12, No. 1 (January 1962): 22–28; Scott H. Dewey, “‘The Antitrust Case of the Century’: Kenneth F. Hahn and the Fight Against Smog,” Southern California Quarterly Vol. 81, No. 3 (Fall 1999): 341–376; Bill Dredge, “Anti-Smog Devices for 1963 Cars Scheduled; Positive Crankcase Ventilating System Will Be Used, Auto Manufacturers Say,” Los Angeles Times 7 December 1961: B8; Jim Dunne, “Detroit Report,” Popular Science Vol. 190, No. 1 (January 1967): 56 ; “52nd Annual Engineering Specifications & Statistical Issue,” Automotive Industries Vol. 142, No. 6 (15 March 1970); “Foreign Auto Makers Warned on Smog Units,” New York Times 28 September 1966: 36; George Getze, “Anti-Smog Devices Ordered for All Autos Sold in 1964; Crankcase Controls Given OK,” Los Angeles Times 19 December 1962: A1, A8; “Smog Controls of 13 Auto Makers Approved for ’68,” Los Angeles Times 13 July 1967: 3; and “State Granted Stringent Auto Smog Controls,” Los Angeles Times 3 May 1969: OC1; Jerry Gillam, “Senate Sends Auto Smog Bill to Governor,” Los Angeles Times 13 June 1965: 1, 20; Tom Goff, “Hahn Demands Recall of ’66 Cars; Hits Smog Devices as ‘Failure,'” Los Angeles Times 9 February 1967: B1–B2; Stuart Griffin, AP, “Smog Poisons Tokyo’s Air—Just Like in L.A.,” Los Angeles Times 28 August 1966: E10; A.J. Haagen-Smit, “The Air Pollution Problem in Los Angeles,” Caltech Engineering and Science Vol. 14, No. 3 (December 1950): 7–13; “Chemistry and Physiology of Los Angeles Smog,” Industrial and Engineering Chemistry Vol. 44, No. 6 (June 1952): 1342–1346; and “The Control of Air Pollution in Los Angeles,” Caltech Engineering and Science Vol. 18, No. 3 (December 1954): 110–16; Kenneth Hahn, Supervisor, Second District, County of Los Angeles Board of Supervisors, A Factual Record of Correspondence Between Kenneth Hahn, Los Angeles County Supervisor, and the Presidents of General Motors, Ford, and Chrysler Regarding the Automobile Industry’s Obligation to Meet Its Rightful Responsibility in Controlling Air Pollution from Automobiles, February, 1963–January 1967 (Los Angeles: County of Los Angeles, 1967); Gerhardt C. Hass, “California Explains Its New Exhaust Standards,” SAE Journal Vol. 68, No. 9 (September 1960): 34–37; Michio Hashimoto, “History of Air Pollution Control in Japan,” How to Conquer Air Pollution: A Japanese Experience, ed. Hajime Nishimura (Amsterdam: Elsevier Science Publishers B.V., 1989): 1–94; Gerhardt G. Hass and Miles L. Brubacher, California Motor Vehicle Pollution Control Board, “A Test Procedure for Motor Vehicle Exhaust Emissions,” Journal of the Air Pollution Control Association Vol. 12, No. 11 (November 1962): 505–543; Gerhardt C. Hass, California Department of Public Health, and J.R. Scanlin, California Motor Vehicle Pollution Control Board, “The Control of Crankcase Hydrocarbon Losses,” SAE Technical Paper 723B (630425) (New York: Society of Automotive Engineers, Inc., 1963); Gerhardt C. Hass, California Department of Public Health, M. P. Sweeney, California Motor Vehicle Pollution Control Board, and J. N. Pattison, Truesdail Laboratories, “Laboratory Simulation of Driving Conditions in the Los Angeles Area,” SAE Technical Paper 660546 (New York: Society of Automotive Engineers, Inc., 1966); Charles M. Heinen and Walter S. Falgey Jr., “Smog – The Learning Years–Building the 88th Story,” SAE Technical Paper 890813 (Warrendale, Pa.: Society of Automotive Engineers, Inc., 1989); Gladwin Hill, “California Adds Auto Smog Curb; Third Such Device Is Made Mandatory in ’70 Models,” New York Times 21 April 1968: 63; S. Kent Hoekman and J. Steve Welstand, “Vehicle Emissions and Air Quality: The Early Years (1940s–1950s),” Atmosphere Vol. 12, No. 10 (October 2021): 1354; Roger Huntington, “More Smog Control = More Expense to the Driver,” Car Life Vol. 12, No. 7 (August 1965): 22–24; Dale H. Hutchison and Francis R. Holden, Stanford Research Institute, “An Inventory of Automobile Gases,” Journal of the Air Pollution Control Association Vol. 5, No. 2 (August 1955): 71–74, 118; Thomas A. Huls, Environmental Protection Agency, “Evolution of Federal Light-Dut Mass Emission Regulations,” SAE Transactions Vol. 82, Section 3 (1973): 1872–1893; James E. Krier and Edmund Ursin, Pollution and Policy: A Case Essay on California and Federal Experience with Motor Vehicle Air Pollution (Berkeley and Los Angeles: University of California Press, 1977, 2019); Ronald E. Kruse and Thomas A. Huls, Environmental Protection Agency, “Development of the Federal Urban Driving Schedule,” SAE Technical Paper 730553 (New York: Society of Automotive Engineers, Inc., 1973); Gordon P. Larson, George I. Fischer, and Walter J. Hamming, “Evaluating Sources of Air Pollution,” Industrial & Engineering Chemistry Vol. 45, No. 5 (May 1953): 1070–1074; John A. Maga and Gerhardt C. Hass, California Department of Public Health, Bureau of Air Sanitation, “The Development of Motor Vehicle Exhaust Emissions Standards in California,” Journal of the Air Pollution Control Association Vol. 10, No. 5 (October 1960): 393–396, 414; John A. Maga, Harmon Wong-Woo, and Milton G. Mason, California Department of Public Health, Bureau of Air Sanitation, “A Status Report on Motor Vehicle Pollution in California,” Journal of the Air Pollution Control Association Vol. 17, No. 7 (July 1967): 435–438; 5tanley H. Mick and John B. Clark, Jr., GM Engineering Staff, “Weighing Automotive Exhaust Emissions,” SAE Technical Paper 690523 (New York: Society of Automotive Engineers, Inc., 1969); John T. Middleton, J.B. Kendrick Jr., and H.W. Schwalm, “Smog in the South Coastal Area,” California Agriculture Vol. 4, No. 11 (November 1950): 7–10; Stanley H. Mick and John B. Clark Jr., GM Engineering Staff, “Weighing Automotive Exhaust Emissions,” SAE Technical Paper 690523 (New York: Society of Automotive Engineers, Inc., 1969); “Other Cities Fight Smog Problems,” Los Angeles Times 14 May 1956: A1, A32; Panel on Electrically Powered Vehicles, Commerce Technical Advisory Board, U.S. Department of Commerce, The Automobile and Air Pollution: A Program for Progress Part II: Subpanel Reports to the Panel on Electrically Powered Vehicles (Washington, D.C.: U.S. Government Printing Office, December 1967); Richard A. Prindle, M.D., MPH, and Charles D. Yaffe, M.S., “Motor Vehicles, Air Pollution, and Public Health,” Public Health Reports Vol. 77, No. 11 (November 1962): 955–962; “Reagan Appoints Nine to Air Resources Board,” Los Angeles Times 21 December 1967: A9; Richard Rutter, “Haze Surrounds Exhaust Purifier; Coast Use Fails to Clarify Future of Auto Devices,” New York Times 5 December 1965: F1, F14; “Showdown Near on Auto Fumes; California Board Will Rule on Exhaust Devices,” New York Times 10 August 1964: 47; “Smog-Control Unit Set for California in ’66-Model Cars,” New York Times 13 August 1964: 39; State of California, Department of Public Health, Technical Report of California Standards for Ambient Air Quality and Motor Vehicle Exhaust (Berkeley, Calif.: California Department of Public Health, 1960); State of California, Motor Vehicle Pollution Control Board, Report to Governor Edmund G. Brown and the Legislature, 12 January 1961, and Report to Governor Edmund G. Brown and the State Legislature, January 1963; “State Officials Tighten Auto Exhaust Controls; California Regulations Made to Conform With New Federal Standards on Emissions,” Los Angeles Times 11 August 1966: 27; “State’s Smog Control Officer Resigns Post,” Los Angeles Times 15 March 1968: 27; William K. Steinhagen, George W. Niepoth, and Stanley M. Mick, GM Engineering Staff, “Design and Development of the General Motors Air Injection Reactor System,” SAE Technical Paper 660106 (New York: Society of Automotive Engineers, Inc., 1966); Bob Thomas, “Automotive: Anti-Smog Clock Running Out for Import Makers,” Los Angeles Times 11 June 1967: D9; “Automotive: Imports Offer Some New Ways to Combat Smog,” Los Angeles Times 16 July 1967: J10; and “Automotive: The Beetle Automatic—VW Is Going ‘Shiftless,'” Los Angeles Times 24 September 1967: H11; Wayne Thoms, “Smog: Blame It on the Car!” Car Life Vol. 12, No. 12 (January 1966): 32–34; UPI, “Auto Industry Opposes Speedup on Smog Curb,” New York Times 25 June 1964: 20; “Auto Smog Device OK’d,” The Desert Sun [Palm Springs, Calif.], Thursday, 9 November 1961: 5; “Brown Signs Anti-Smog Act to Set Exhaust Standards,” Oxnard Press-Courier [Oxnard, Calif.] 29 April 1959: 9; “California to Require Cars to Add Air-Control Devices,” New York Times 26 September 1963: 52; U.S. Department of Health, Education, and Welfare, Automotive Air Pollution: Second Report of the Secretary of Health, Education, and Welfare to the United States Congress Pursuant to Public Law 88–206, the Clean Air Act (Washington, D.C.: June 1965); Office of the Surgeon General, Motor Vehicles, Air Pollution, and Health: A Report of the Surgeon General to the U.S. Congress in Compliance with Public Law 86–493, The Schenk Act (87th Congress, 2nd Session, House Document No. 489) (Washington, D.C.: U.S. Government Printing Office, July 1962); U.S. Department of Health, Education, and Welfare, Public Health Service, National Center for Air Pollution Control, A Digest of State Air Pollution Laws, 1967 Edition (Washington, D.C.: U.S. Government Printing Office, 1967); U.S. Department of Health, Education, and Welfare, Public Health Service, Abatement and Control Development Program, A Compilation of Selected Air Pollution Emission Control Regulations and Ordinances, rev. ed. (Washington, D.C.: U.S. Government Printing Office, 1968); United States Senate, Eighty-Ninth Congress, Air Pollution Control: Hearings Before a Special Subcommittee on Air and Water Pollution of the Committee on Public Works, United States Senate, Eighty-Ninth Congress, First Session, on S. 306 (Washington, D.C.: U.S. Government Printing Office, 1965); United States Senate, Ninetieth Congress, Air Pollution—1967 (Automotive Air Pollution): Hearings Before the Subcommittee on Air and Water Pollution of the Committee on Public Works, United States Senate, Ninetieth Congress, First Session on Problems and Progress Associated With Control of Automobile Exhaust Emissions, Part 1 (Washington, D.C.: U.S. Government Printing Office, 1967); and Howard P. Willens, “The Regulation of Motor Vehicle Emissions,” Natural Resources Lawyer Vol. 3, No. 1 (January 1970): 120–130.

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