vehicles. Since all oxidation catalysts are poisoned to some extent by lead in the gasoline, the replacement of a catalyst will be an important factor in the cost to the public. Thus, the ultimate success of this process is dependent upon an inexpensive catalyst which will have a reasonably long life. OxyCatalyst recently has reported the development of such a catalyst. The reports on the use of this catalyst, at its present stage of development, show a reduction of hydrocarbons and other partly burned materials in excess of 85 percent averaged over 10,000 miles of driving. The catalyst is of practical size and weight for application to passenger vehicles.

The Clayton Manufacturing Co. in Los Angeles has reported the development of an afterburner device employing a spark plug to ignite the mixture in the exhaust of engines above 600 cubic inches displacement. Laboratory reports show 90 percent elimination when the combustion chamber of this equipment has reached 1,200° F. No report is available on starting the apparatus, or the degree of elimination when the vehicle is on the road. Several of these devices are being installed on gasoline-engine buses in California.

While the analytical data show only small quantities of contamination coming from diesel engines, the odor problem is of serious concern in underground operations, in closed areas, and in the immediate proximity of these vehicles at street level. Proper maintenance of diesel engines is an important factor in minimizing the odor complaints. However, here again, neither changes in fuel or maintenance will eliminate the problem.

Serious difficulties are encountered in removing the small amount of contamination present in the diesel exhaust. The employment of an oxidation catalyst on this exhaust, without the addition of some fuel, is out of the question on a two-cycle engine. Oxy-Catalyst has demonstrated a prototype unit employing small additions of fuel and a heat exchanger in the muffler to eliminate successfully the smoke and odor. This catalytic process is being tested by a diesel-engine manufacturer, with the view to solving certain engineering problems and determining size and cost factors. This same company currently is marketing a muffler for four-cycle engines which gives some degree of relief where the engine is under load for a good portion of the time.

No successful work has been reported on direct chemical treatment or scrubbing systems for exhausts, except for stationary engines in underground operations. Even here, such processes are costly and of low efficiency. More than 25 universities, private research laboratories, and industrial concerns currently are engaged in studying the many aspects of this complex problem. It is a certainty that several solutions will be proposed and there is reason to believe that progress will be made toward the final goal.

At present, it appears that the application of oxidation catalysts to the exhaust problem offers the best promise for an immediate solution. The organic substances which create the worst air pollution and health problems can be rendered harmless. Carbon monoxide can be oxidized readily and carbon and smoke particles greatly reduced. The use of an appropriate oxidation catalyst also holds promise of reducing the oxides of nitrogen which are so important in confined areas.

The important contribution of Eugene J. Houdry of a new lead-resistant, lowcost catalyst to do this job is a major step forward. The final cost to the public should be promptly determined and weighed in terms of good public relations and the desire to provide a cleaner environment.

REFERENCES

(1) Larson, G. P., Recent Identification of Atmospheric Contaminants in the Los Angeles Basin. Proc. 44th Annual Meeting Ap-SPA, 127-133 (1951).

(2) Conn, G. R., Noble, W. M., and Larson, G. P., Detection of Smog Forming Hydrocarbons in Automobile Exhausts Using Plants as Indicators. Air Repair, 4, No. 2 (Aug. 1951).

(3) Haagen Smit, A. J., Chemistry and Physiology of Los Angeles Smog. Ind. Eng. Chem. 44, 1342 (1952).

(4) Larson, G. P., Chipman, J. C., and Kauper, E. K., Distribution and Effects of Automotive Exhaust Gases in Los Angeles. Society of Automotive Engineers Transactions 63, 567–574 (1955).

(5) Los Angeles County Air Pollution Control District, Second Technical and Administrative Report on Air Pollution Control in Los Angeles County.

(6) Twiss, 2B, et al., Applications of Infra-Red Spectroscopy to Exhaust Gases. Air Repair 5, 75-83 (Aug. 1955).

(7) Elliott, M. A., et al., The Composition of Exhaust Gases from Diesel Gasoline and Propane Powered Motor Coaches. Air Repair 5, 103-1-8 (Aug. 1955).

(8) Haagen Smit, A. J., Ozone Formation in Photochemical Oxidation of Organic Substances. Ind. Eng. Chem. 45, 9–53.

(9) Kotin, P., et al., Aromatic Hydrocarbons: Their Fate Following Emission into the Atmosphere and Experimental Exposure. A. M. A. Arch. Ind. Health 13, 13-17 (Jan. 1956).

(10) Chandler, J. M., et al., Engine Variables and Their Effects on Exhaust Gas Composition. Air Repair 5, 65–70 (Aug. 1955).

(11) Calvert, W. R., Catalysts at Work Eliminating Air Pollutants. APCA Meeting, Buffalo, N. Y., May 1956-In print.

Mr. LOSER. I have the impression that you have this almost solved. Mr. LARSON. On the basis of finding the catalyst, applying it, applying it to a vehicle on the road, the fundamentals of the problem are solved.

There remains the determination of the final cost in mass production, and its actual application, sizewise, and fitting, to automobiles. Mr. LOSER. I believe you fix the cost at a maximum of $30.

Mr. LARSON. That is what it appears to us to be. We are catalyst manufacturers, and we are studying the mass production problem of the metal manufacturing. That will determine the final cost.

Mr. LOSER. Without objection, the additional statement of Mr. Larson has been incorporated in the reference. That is a review of the pollution problems for engine exhaust.

Thank you very much.

Mr. Schenck.

Mr. SCHENCK. Mr. Chairman, I do not have any question to ask Mr. Larson, but I want to express my grateful appreciation for his fine statement and for indicating that this can be done.

Thank you.

Mr. LOSER. Mr. Larson, if you would remain a moment, it is possible that these other gentlemen might want to ask you a question or

two.

Mr. Beamer.

Mr. BEAMER. I have one question, Mr. Chairman.

I do not want to pry into the affairs of your corporation, but has this been presented to the automotive industry, and, if so, what has been their reception?

Mr. LARSON. The automotive industry has conducted tests over the past year of this catalytic process, and we are in the course of studying various approaches to the next stage of the problem, which is studying the final cost and fitting the application to the automobile. Mr. BEAMER. Have you received some encouragement from the industry?

Mr. LARSON. Yes. We have had the finest of cooperation, and the test of the catalyst has only been very recently completed by them. Mr. BEAMER. Thank you, Mr. Chairman.

Mr. LOSER. Mr. Bush?

Mr. BUSH. Congressman Beamer asked the same questions that I had in mind.

I just wondered if you were cooperating with the people in the automotive field, and what your reception was. You seem to be very sure in your answer, and then at the end of your statement you say there is still a lot to be done in the way of engineering and that kind of thing.

Mr. LARSON. There is some more work to be done.

Mr. BUSH. How long is it going to take to do that?

Mr. LARSON. I cannot answer specifically how long. Oxy-Catalyst is studying the problem itself of determining the mass production problem and its cost. We are talking also with metal manufacturers who are interested in this process, and who would be capable of doing the manufacturing and the studies.

We are also talking with the motor industry at the technical level, to determine whether or not they might go ahead with further studies on the manufacturing.

So we are working at the present time on three fronts, and we are at this point today simply because our tests have been completed on what the catalyst will do, and the motor industry has only recently conducted a similar independent test to arrive at what they conclude the catalyst will do.

So we are at this mass production metal study of the problem right now on three fronts.

Mr. BUSH. Thank you very much.

You are from a great State. I happen to be from Pennsylvania myself.

STATEMENT OF DR. WILTON M. FISHER, CHIEF, AIR POLLUTION MEDICAL PROGRAM, DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE, WASHINGTON, D. C.

Mr. LOSER. This is Dr. Wilton M. Fisher, Chief of Air Pollution Medical Program, Division of Special Health Services, from the Department of Health, Education, and Welfare, here in Washington. You may proceed.

Dr. FISHER. Thank you, sir. We have supplied a written statement on the first two questions asked in your letter, sir, of March 1.

On the third question, the status of research on controlling air pollution through modification of automobile design, we were reasonably certain when talking to Mr. Jones that it would be covered during the morning, and then it seems that it was.

Most of the question on the extent to which the automobile may be contributing to the air-pollution problem was covered by Mr. Griswold. We have some additional summary statements supplied in the

written text.

Mr. LOSER. Without objection, your written statement will be made a part of the record. We would be glad if you want to make some oral observations in connection with the matter.

Dr. FISHER. Thank you, sir.

(The document referred to follows:)

DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE,

Hon. KENNETH A. ROBERTS,

PUBLIC HEALTH SERVICE,

BUREAU OF STATE SERVICES, Washington, D. C., March 14, 1958.

Chairman, Special Subcommittee on Traffic Safety, Committee on Interstate and Foreign Commerce, House of Representatives.

DEAR MR. ROBERTS: As a technical representative of the Public Health Service, Department of Health, Education, and Welfare, and as chief of the air pollu tion medical program of the Division of Special Health Service, I am pleased to have the opportunity to assist your committee in its hearings on H. R. 9368. Attached to this letter are statements concerning (1) the present status of research on the toxicity of fumes on human beings; (2) the possible extent of automotive contribution to the air-pollution problem. Mr. Jones of your staff agreed that the third area in which you had indicated the interest of your committee, the status of research on the possibility of controlling some of the air-pollution problem through a modification of automobile design, can best be presented by other witnesses.

Sincerely yours,

WILTON M. FISHER, M. D.,

Chief, Air Pollution Medical Program, Division of Special Health Services. THE PRESENT STATUS OF RESEARCH ON THE TOXICITY OF (AUTOMOBILE) FUMES ON HUMAN BEINGS

The major responsibility of the air pollution medical program of the Public Health Service is to determine whether or not community air pollutants modify the public health. Our concern is with all air pollution and not alone with that arising from the automotive engine. Our broad program at the present time does, however, provide for studying some fundamental problems in regard to the effects of certain components and groups of air components of air pollution connected with the use of the automobile. I shall discuss some of these later. The interest of the Public Health Service and other Federad agencies in the automotive engine as a source of air contaminants which are of possible concern to the public health extends back at least 30 years. In 1927 and 1928 studies were made both by the Public Health Service and the Bureau of Mines of the problem of the auto exhaust and public health. These studies were made to clarify the problem as it related to carbon monoxide and tetraethyl of lead. It was the conclusion at that time that the discharge of carbon monoxide into community air, as long as it was not permitted to accumulate in confined spaces, was not of health signicance. It was also concluded that tetraethyl of lead, in the very small amounts that were then added to gasoline, did not create a health hazard from the auto exhausts that reached the community ambient air. Although these are the prevailing opinions in the United States, even to the present time, we do not wish to leave the erroneous impression that these opinions are unanimous. Certainly they are not unanimous internationally, judging from the available medical literature on the subject. These two components of automobile exhausts, carbon monoxide, and lead compounds, have over the years continued to receive attention from scientists concerned with the public health. Finally, I must add that the possible hazard created by these materials may be changing, due partly to the increasing numbers of automotive units producing the exhausts and the engineering advances made by the automobile industry.

Over the years the other components known to be present in automotive exhausts have received some attention for public-health reasons; but, the amount of that attention has been less than the amount generally given to carbon monoxide and lead. Undoubtedly many possible reasons come to mind for these differences in emphasis, and I shall not go into these at this time. The need for consideration of the other components of auto exhausts has been emphasized recently.

I should like to review at this time for you the significant points which, as it seems to me, make it useful to evaluate the problem of the automotive exhaust gases and public health. Briefly, I shall consider this under two headings: Cancerigenic properties and irritative properties of auto exhausts.

It has been shown that auto exhausts contain substances which, when supplied to suitable experimental animals under appropriate conditions, will increase the

frequency of cancer. There has been some question of the relative amounts of carcinogenic agents discharged with the exhaust gases, but there has been little denial that such agents are so produced.

Incidentally, it may be noted that polycyclic hydrocarbons of known carcinogenic potency have been produced from the burning of even very simple hydrocarbons under special experimental conditions.

This is not to say that only the polycyclic hydrocarbons are implicated in experimental cancer production. Straight-chain hydrocarbons have also been claimed as culprits. Such straight-chain hydrocarbons may be active in more than one way. They have been shown to have a carcinogenic potential per se. But what may be of even greater significance in connection with the carcinogenicity of the straight-chain hydrocarbons is that they serve as solvents for, and carriers of, more potent polycyclic hydrocarbons, thus bringing the latter into more effective contact with the target issue.

Although the irritant property of automobile exhausts is discussed later, I must mention it at this point, since this property may have a significant relationship to the cancer potential of the exhaust gases.

Irritation per se may have a serious carcinogenic potential. Auerbach, of the Veterans' Administration, in his study of tobacco smoke and cancer, has shown that irritation of the mucosa of the tracheobronchial tree leads to hyperplasia and even to metaplasia of the mucosal lining. Although by inference one may see a relation between such metaplasia and bronchiogenic carcinoma, it is not possible to conclude that such metaplasia as is found in these cases will lead to carcinoma. Such irritation, however, may act in either of the two ways to be a factor in carcinogenesis. These are:

(a) Irritation, if it is mild, will cause a slowing down of the activity of the cilia of the mucosa of the air passages, and this will permit a longer period of contact between inhaled potential carcinogenic agents and the susceptible tissue. (b) When the irritation is severe, denundation of the surface layers of the epthelium of the tracheobronchial tree will occur and thus the deeper more susceptible cells will be exposed to the action of any potential carcinogenic material that may be carried in the breath.

A final point to be made is that there has been a universally growing increase in lung cancer frequency. During the time that this fact has been recognized various environmental factors have been blamed for this increase. In regard to auto exhausts, I may say we know of no scientific data that have shown that the automotive engine exhaust specifically is, or is not, responsible for part of this increase of lung-cancer frequency. Although we strongly suspect relationship between air pollution and lung cancer, we do not now know that air pollutionconsidered in its entirety, of which auto exhausts provide only one part-is, in fact, related to the increase of lung-cancer frequency.

Now, if I may discuss some of the irritant qualities of auto exhausts, I will go on to say that automotive engine exhausts can irritate exposed membranous surfaces-eyes, nose, throat, and respiratory tract is denied by no one who has ever had to stand about in a closed garage in which an engine was running. In such instances the gases were allowed to accumulate in a confined space to reach significantly high levels of concentration.

The eye-irritation phenomenon, at times complicated by throat irritation, that has been observed in the Los Angeles Basin, and to a lesser extent in other places, seems to be temporally associated with automotive traffic. According to California studies, this phenomenon is associated with vegetation damage and air haze. It is generally accepted that meteorology and topography are related to the occur. rence of the eye-irritation phenomenon. This eye condition, to the best of our knowledge, is a subjective phenomenon and is manifested by discomfort and tearing and is not associated with any measurable eye injury. If for no other reasons, the symptom of eye irritation is of public-health significance, since it is associated with an unmeasured degree of apprehension among the residents, apprehensions as to what such an airborne irritant may be doing to their health.

We have been sufficiently impressed with the potential toxicity of certain exhaust components to spend considerable amounts of our moneys and our efforts to support studies of biological effects of auto exhaust gases, especially as regards certain components of those gases.

One of these that we are supporting is that being done by Dr. Joseph Gast at Baylor University College of Medicine, ouston, Tex. At our request he developed a mechanical unit to combine oxides of nitrogen with gasoline-contained hydrocarbons, irradiate the mixture with ultraviolet radiation, and to