distribution and the general use of tetraethyl lead gasoline motor fuel.

On January 19, 1926, a second conference was held at which the report of the committee was presented. The committee concluded that there are at present no good grounds for prohibiting the use of ethyl gasoline of the composition specified as a motor fuel provided that its distribution and uses are controlled by proper regulations.

This conclusion was qualified by the statement that, although the study was most careful and conscientious, it was subject to criticism because of the relatively small number of individuals exposed to the effects of ethyl gasoline for a comparatively brief period of time.

The committee also noted that it remains possible that if the use of leaded gasoline becomes widespread, conditions may arise very different from those studied by us which would render its use more of a hazard than would appear to be the case from this investigation. For these reasons, the committee recommended that the study be continued to determine any potential menace to the health of the general public after prolonged use or under conditions not foreseen at that

time.

Senator MUSKIE. May I ask you, was there any question that the deaths to which you referred were traceable to the tetraethyl lead? Dr. PRINDLE. Čertain deaths were definitely traceable. However, these were industrial exposures of very high concentrations. For example, men cleaning out a tank car which had contained this, being in this closed atmosphere. So these were very acute episodes compared to what we anticipate the population will be exposed to. The committee recommended that the amount of tetraethyl lead be limited to approximately 3 cubic centimeters per gallon of gasoline. This recommendation and a number of others affecting the general use, handling, manufacture, and blending of tetraethyl lead were included in regulations which were presented to and approved by the Conference of State and Territorial Health Officers on May 25, 1926. The restriction on the sale and distribution of tetraethyl gasoline was removed shortly thereafter.

Senator MUSKIE. May I ask you this question?

The Surgeon General apparently had the authority at this time to discontinue the use of the tetraethyl lead.

Dr. PRINDLE. To be quite honest, Mr. Chairman, I don't believe he did have that authority.

Senator MUSKIE. Does he have authority now to take a similar step if he felt that hazards to public health required it?

Dr. PRINDLE. I don't believe the authority is any different at this time with regard to this type of situation.

Senator MUSKIE. Would he regard the 1925 incident as establishing a precedent which he could rely on to take similar action today?

Dr. PRINDLE. I don't know if he could rely upon it. It is a precedent that might be followed.

Following the 1926 Conference of State and Territorial Health Officers, the president of the Ethyl Corp., which at that time was the sole producer, voluntarily agreed to manufacture, blend, and market TEL and leaded gasoline in accordance with the intent of the recommended regulations.

This statement of intent served to establish standardized nationwide safety procedures and apparently removed the pressure for State regulations. Subsequently, no State or Federal law has been enacted pertaining to the hygenic aspects of TEL. In addition, the recommended regulations were adopted as understandings by many national governments and have provided a basis for worldwide health and safety practices by TEL manufacturers and petroleum refiners. Senator MUSKIE. Let me ask you this, Dr. Prindle, would you be in a position to recommend legislation, too, provided you had the authority or the Surgeon General had the authority to be exercised under guidelines which you might be in a position to spell out?

Dr. PRINDLE. I think we would be very interested in considering such approaches. I think not only with respect to this problem but many of the other environmental problems which we are facing. We are going to need a stronger Federal role in many of these kinds of activities and certainly some approach of this type should be given consideration.

When the E. I. du Pont de Nemours Co. began marketing TEL in 1946, the company advised the Surgeon General that it would abide by the intent of the recommended regulations.

In 1958 the Ethyl Corp. requested the advice of the Public Health Service on increasing the maximum amount of tetraethyl lead from 3 to 4 cubic centimeters per gallon in order to keep pace with fuel requirements dictated by modern automobile engines. Parenthetically, it should be noted that the national average use in this of lead alkyls in gasoline amounts to somewhat less than 60 percent of this maximum. About 2.4. In other words, what I am saying is that manufacturers may use up to 4 cubic centimeters but in fact as a national policy when you average this all out it turns out to be about 2.4 cubic centimeters.

Early in 1959 the Surgeon General appointed an ad hoc committee to evaluate the proposed increase in gasoline lead in terms of its possible effect on health. The ad hoc committee, composed of Public Health officials, officials of State and local health and air pollution_control agencies, and industrial authorities on hygiene, advised the Surgeon General that the proposed increase in lead apparently would pose no health hazard, but that more research was needed on levels of atmospheric lead in urban areas and on their relationship to amounts of lead in human beings.

Senator MUSKIE. May I ask you this? Did the Surgeon General at that time have the evidence which the Surgeon General this morning presented to the committee which raises such obvious questions?

Dr. PRINDLE. I don't think that much evidence was available at that time. Frankly, I think very little had been done on the lead problem when-between the period of 1925, 1926 and the period we are now talking about, the period of 1959. It was not until this second move to increase the amount of lead that the picture really became more evident as a problem. I think it is only subsequent to this second. situation that most of the work which has been described was made available.

There had been considerable lead research being carried out, much of it by the industry or under the sponsorship of the industry. Much

of this had been related to the occupational problems and not so much to this community problem with which we are concerned today.

Senator MUSKIE. Would it not have been wiser for the Surgeon General to have initiated the research before he approved the increase rather than subsequent to approval?

Dr. PRINDLE. I don't believe I would be in a position to judge exactly what the background of this was. I think the situation was very much one of tremendous pressure, frankly, to move forward in what amounts to an economic problem so far as industry was concerned. This was attempted therefore in the light of the knowledge. As I mentioned earlier, increasing this on paper to 4 cubic centimeters in fact had relatively little to do apparently with the national average pool. This was definitely a factor that was kept in mind in allowing this increase.

Senator MUSKIE. I realize that it is something like Monday morning quarterbacking to judge the action taken. On the other hand if I am out in the woods hunting deer I don't shoot at a moving leaf but wait until I see something more.

Dr. PRINDLE. I think you are probably correct, Senator.
Senator MUSKIE. Thank you.

Dr. PRINDLE. Acting on the committee's recommendation, the Surgeon General invited the automobile industry, gasoline and lead antiknock producers to join with the Public Health Service in a survey of atmospheric lead in selected cities and of lead concentrations in blood and urine of persons living in the same cities.

The lead studies were conducted in Cincinnati, Philadelphia, and Los Angeles between May 1961 and June 1962 under the auspices of the Division of Air Pollution. In each city, air sampling devices were stationed in selected areas representing commercial, industrial, residential and rural types.

The amounts of airborne lead, as determined by laboratory analysis of filters through which measured amounts of ambient air were drawn, were found to be lowest in rural areas and highest in midcity commercial zones. The ratio between lead concentrations in rural and downtown air was 1 to 2 in Cincinnati, 1 to 3 in Philadelphia, and 2 to 3 in Los Angeles.

The average concentration of lead in all samples collected in each city was 1.4 micrograms per cubic meter of air-a microgram being a millionth of a gram, so these are very small amounts we are dealing with-in Cincinnati, 1.6 in Philadelphia, and 2.5 in Los Angeles. Samples taken in heavy vehicular traffic were considerably higher. Fourteen micrograms per cubic meter in congested traffic on Cincinnati streets and 25 micrograms per cubic meter on Los Angeles free

ways.

The concentration of lead in the blood of some 2.300 individuals representing all three cities was determined. Eleven persons showed concentrations of lead in the blood equal to or exceeding 0.06 milligram per 100 grams of blood-6 parts in 10 million. In the occupational health field, when blood levels reached 0.06 milligram per 100 grams of blood, the worker is normally removed from an environment in which lead exposure can occur. This is a safety measure. Concentration of 0.08 milligrams of lead or more per 100 grams of blood are associated with toxic lead poisoning

The clincal type that Dr. Stewart described. I would point out the small difference between 0.06 milligrams or 6 parts per 10 million and 8 parts per 10 million is not a very marked margin of safety.

Senator MUSKIE. How quickly could that gap be closed by exposure to ambient air in one of the three cities studied?

Dr. PRINDLE. It probably would take a fair amount of time if we are talking about the kinds of concentrations that are averaged here. If one took an individual who for a variety of reasons had a fairly heavy lead exposure and perhaps standing 24 hours a day on the Los Angeles freeway, if he were not run over might lead to this other problem.

Senator MUSKIE. Well, a traffic policeman might.

Dr. PRINDLE. Yes, sir. They were amongst the kind of people we found having higher levels than the others.

Senator MUSKIE. Service station attendants?

Dr. PRINDLE. Yes, sir.

Senator MUSKIE. Or a traveling salesman.

Dr. PRINDLE. I don't believe we have one of those to help us out in this case.

The data on lead in the blood of the subjects in the three-city study were examined in relation to a number of variables. All of the 11 persons with high lead levels had histories conducive to greater than average exposure. No relationship was found between levels of lead in the blood and age. Levels in females were slightly lower than those in males from comparable groups.

In nearly all instances the mean concentration of lead in the blood of smokers was slightly higher than that of nonsmokers. We observed no unusual findings concerning persons who were investigated because they had chronic diseases of one kind or another.

We noted a general trend toward an increase in concentration of lead in the blood of the various groups of persons as they vary from rural to central urban areas in their places of residence and work. For example, those who lived and worked in rural or suburban areas had the lowest concentration of lead in their blood and it was in these areas that the lowest concentrations of lead were found in the atmosphere. Highest mean levels of lead in the blood were noted for groups who worked and in some areas lived in areas characterized by higher concentrations of lead. These relationships were not as well defined for intermediate levels of lead in blood and in the atmosphere.

Our working group on lead contamination completed its work toward the end of 1964. In January 1965, the Public Health Service published a report of the studies. We did not look with complacency on the fact that out of 2,300 persons studied we found 11 who were in danger of ill health from lead exposure.

If these data were generalizable, and I quickly say I don't believe they are but if they were generalizable, to the U.S. population, one might expect to find between one-half and 1 million persons affected as these 11 were.

Our findings made it clear to us that we needed to conduct further investigations and update our knowledge on all aspects of lead contamination.

In December 1965 we sponsored a symposium on environmental lead contamination at which we brought together persons representing the

widest possible range of informed scientific opinion on the subject of lead. We called the symposium as a first step toward assessing, more adequately than had been done before, the role of lead as an environmental contaminant to which all people are exposed.

In general, two principal points of view were expressed at the symposium to put it in its extreme, one by those who apparently feel that there is nothing to be alarmed about until the levels of lead in the blood of the ordinary population have virtually reached the level at which acute and clinically recognizable lead poisoning occurs; a second, by those who feel that any rise in levels of lead in the blood is hazardous.

The principal lesson I learned from the symposium is that we simply do not have the data we need to determine to what extent control action may be necessary to curb human exposure to lead in the urban environment.

To find out the real dimensions of the problem of lead contamination and to provide a pattern for research and control programs for other environmental contaminants as well, a good deal of work, new work will need to be done.

For example, we need to know more specifically which people in the urban population have body accumulations of lead that can be considered hazardous and precisely who these people are in terms of occupation, smoking habits, and so forth.

This kind of information can be derived from epidemiological studies focused particularly on those special population groups which, as Dr. Stewart pointed out, we have reason to suspect may be more highly exposed as well as those who may be more susceptible to ill effects from lead. Almost all of the exposure data currently available is derived from studies of the healthy, working male.

To assess national trends with regard to the distribution of lead in the environment, we must have coordinated monitoring programs to determine the concentration of lead in food, air, and water. Such work would require extensive cooperation with other Federal agencies.

To exercise meaningful surveillance over the many environmental contaminants of a radiological or chemical nature which may now, or may in the future, be a threat to human health, I plan to establish within the Bureau a scientifically oriented office which, utilizing systems analysis and program evaluation procedures, would be charged with accomplishing the following:

1. Coordination of the activities of the various categorical environmental health programs such as the pesticides program, Division of Air Pollution, Division of Radiological Health, Division of Occupatonal health et cetera, insofar as these relate to environmental contaminants which may reach man through two or more vectors in the environment.

2. Constant surveillance to determine precisely which facets of environmental contamination are increasing and to recommend where attention is needed.

3. Maintenance of liaison with the National Institutes of Health with regard to more fundamental research in the life sciences and as a means of assuring that research at the National Institutes of Health and elsewhere at universities, institutions and other agencies, is evaluated in relation to problems of environmental contamination.