lish the presence of similar harm in any of the others, would the option of addressing the cause of harm to the first individual then be forgotten about?

Dr. KARRH. No. We would investigate the first individual to see what could have caused that person to have experienced the adverse health effect, investigate the job they were doing, their workplace, the way they handled the job, the types of equipment that they were using and try to determine why they were different from the others as far as their experiencing some health effect from the job.

Only after we had totally excluded the possibility that the job itself was causing it and not just the individual's susceptibility to it would we take any exclusionary action.

But it is very seldom really that removal has to be done; removal from a job is not a frequent occurrence because of individual susceptibilities.

Mr. GORE. In what percentage of cases would corrective action consist of medical removal?

Dr. KARRH. I can't give you a percentage. I can just tell you it would be in very few cases that permanent medical removal would be the preferred course of action.

Mr. GORE. How predictive are liver function and urine metabolite tests?

Dr. KARRH. The liver function tests are not predictive at all. The liver function tests measure physiological changes in the ability of the liver to function, so they are not a predictive test.

The biological monitoring tests are not predictive at all. They are tests for the actual absorption of the material for which you are testing. In the two examples I cited, we check for metabolites of dimethylformamide and dimethylacetamide in the urine of employees who may have been exposed.

The only way that the metabolites can get there is for the person to have been exposed.

I should add, Mr. Chairman, that these tests are really a check on two parameters. One is how effective have our controls been to make sure that we are adequately protecting our employees. Second, to make sure our employees are not suffering any adverse health effects as a result of their jobs.

Mr. GORE. I guess the question is how indicative of those two factors are the tests?

Dr. KARRH. The metabolite tests are very indicative, because nothing else will cause the metabolite to be there. If the metabolite is present in the urine, in the case of the two I cited, if it is present in the urine above a level we have previously determined to be a level that would result from a safe exposure, then we know that person has been overexposed. The liver

Mr. GORE. So you get no false positives?

Dr. KARRH. We have not had any false positives.

Mr. GORE. You might get false negatives?

Dr. KARRH. To my knowledge, we haven't any on those tests either, but that is a possibility. The liver function tests are not specific tests, all they tell you is that the liver has some dysfunction, it is not functioning properly for some reason.

It does not tell you why it is not functioning properly. But by using a battery of tests, doing the investigation we do, and using the metabolite test we do, we can decide whether or not the workplace exposure may have been the cause of the abnormal liver function test.

Mr. GORE. Moving on to a related area, what is Du Pont's policy regarding medical removal of women in the area of reproductive hazards?

Dr. KARRH. We have some few jobs where we have had to exercise what we call special controls because of the embryo-fetotoxic potential of a chemical substance. Out of the 2,500 chemical substances that Du Pont reported to the EPA. For the Toxic Substances Control Act inventory, we have identified only seven chemicals that we do have to exercise special controls because of their embryo-fetotoxic potential.

In cases where we do have to exercise special controls, we will start first with engineering controls to try to reduce the exposure at its source. If we are not successful in reaching a safe exposure level or if we don't know what a safe exposure level is, we will go to personal protective equipment, or work practice controls, in combination with engineering controls.

If those three methods are not successful, we may have to exercise medical removal of women of child-bearing capability.

Mr. GORE. What are the seven chemicals?

Dr. KARRH. The first two are listed in my testimony on the top of page 8, dimethylformamide and dimethylacetamide. Both of those have a threshold limit value set by the American Conference of Governmental Industrial Hygienists and picked up by OSHA, of 10 parts per million in air, but they are readily absorbed through the skin.

If we have a workplace in which employees are exposed to levels that do not exceed 10 parts per million in air and there is no significant opportunity for liquid contact with the skin, then both men and women of child-bearing capability are allowed to work in such areas. If we exceed 10 parts per million in air, although we have almost no places that do, or if there is opportunity for significant liquid contact with the skin, which there are some jobs where that can occur, then women of child-bearing capability would be excluded.

The third one is formamide, which has a threshold limit value of 20 parts per million. Our internal limit for women of child-bearing capability is set the same as for dimethylformamide and dimethylacetamide, 10 parts per million in air with no opportunity for significant liquid contact with the skin.

The third one is ethylenethiourea. It is also carcinogenic and is controlled at a very low level because of its potential to cause cancer of the thyroid. Women of child-bearing capability are not allowed to work jobs in which they can be exposed to ethylenethiourea.

Fortunately, those are very few jobs. The fourth one is hexafluoroacetone; which has a threshold limit value of 0.1 parts per million, set by the American Conference of Governmental Industrial Hygienists based upon its effect on animial spermatogenesis in some work done by Du Pont.

This is the reason for the threshold limit value that has been set at that low level, but it also has an effect on the fetus at levels below that, based upon data that we have.

In jobs in which there is potential for exposure to hexafluoroacetone, women of child-bearing capability would not be able to work. The sixth one is lead and its salts, and this includes a whole family of compounds. Women of child-bearing capability are allowed to work in jobs in which the atmospheric concentration of lead does not exceed 5 micrograms per cubic meter of air or in which the blood level of exposed workers will not exceed 30 micrograms per 100 grams of blood.

The seventh one is ammonium perfluorooctanoate, abbreviated FC-43, and that is a new one based some preliminary data that was developed the first of this year. We found that it did cause an abnormality in the eyes of rats in a preliminary study that was done, at the levels that we thought could be found in the workplace. I am sorry, counsel just reminded me that we did not find it but another company who is our supplier found it and advised us. We felt we had to take the appropriate action until we could further delineate exactly what was the risk to the fetus in those cases. That chemical is still on our list. We currently have studies under way to delineate what is exactly the risk to the human fetus. Mr. GORE. Let's focus in on the case of hexafluoroacetone, Du Pont conducted a study showing that it caused harm to male spermatogenesis.

Dr. KARRH. In laboratory animals, yes.

Mr. GORE. In laboratory animals?

Dr. KARRH. Yes.

Mr. GORE. And based upon the damage found to spermatogenesis, the company decided to exclude fertile females from coming into contact with this chemical?

Dr. KARRH. No, sir.

Mr. GORE. Correct my understanding.

Dr. KARRH. The TLV, threshold limit value, by the American Conference of Governmental Industrial Hygienists, was set based on its effect on animal spermatogenesis. The effect it has on the developing fetus is a separate effect from its effect on the sperm. Mr. GORE. But that was

Dr. KARRH. That was also determined by laboratory animal studies, separately from the spermatogenic effect.

Mr. GORE. I see, all right.

Dr. KARRH. I probably confused you by the way I said that. In addition to having a spermatogenic effect, it also has an embryofetotoxic effect. The special controls which may mean exclusion in some cases, were implemented because of its effect on the embryo or fetus, not because of its effect on the sperm.

But the TLV was set because of its effect on the sperm. The TLV holds for adult female workers not of child-bearing capability and would also apply to adult females who were of child-bearing capability were it not for the fetotoxic effect.

Mr. GORE. The fetotoxic effect was not partly inferred from the spermatogenic effect.

Dr. KARRH. That is correct, it was not.

Mr. GORE. All right. Now, are fertile males excluded from contact with hexafluoroacetone?

Dr. KARRH. No, because we can keep it below the 0.1 part per million level which has been determined a safe level for spermatogenetic effects.

Mr. GORE. But the level for fetotoxic effects is lower than that? Dr. KARRH. That is correct, based upon animal data that we have.

Mr. GORE. And who established that level?

Dr. KARRH. The 0.1 was established by the American Conference of Governmental Industrial Hygienists. The no-contact for the fetus is an internal Du Pont level based upon the data we have.

Mr. GORE. Based upon which data?

Dr. KARRH. The animal test data that we have that indicates it does have an embryo-fetotoxic effect.

Mr. GORE. Is that data quantifiable?

Dr. KARRH. Our toxicologists think it is, but not to a specific number because they cannot extrapolate the data that they have from these animal studies to a level that they can be applied to the human fetus.

Mr. GORE. Was the fetotoxic data developed by Du Pont?

Dr. KARRH. Yes. To my knowledge, it was. I have not looked at it lately but I think it was.

Mr. GORE. I see. What is your opinion concerning the testimony regarding reproductive hazards to men? You heard the first panel.

Dr. KARRH. I think there are some hazards that can be transmitted to the embryo or fetus by exposures of the male. This is a very new area which is poorly understood at present. Some of the studies that have been reported indicate that this area needs more research.

Mr. GORE. Are you contrasting the poor nature of the understanding in this area with the excellent nature of the understanding in the fetotoxicity area?

Dr. KARRH. I don't think we can say it is an excellent understanding in the fetotoxic area. I think it is a little better understood area than the male-mediated reproductive hazards. You are dealing with two different entities. In one, you are dealing with the adult worker, whether it is male or female, and protecting against the most sensitive physiological function or organ system that that adult worker has, whereas in the other case, you are concerned with protecting against an unborn fetus that shows up in the workplace. The employer may or may not know that the employee is pregnant, the employee may or may not know she is pregnant. The period of damage to the fetus or to the embryo is during the period of organogenesis, day 18 through day 60. Many women do not know they are pregnant within the first 18 days after fertilization of the ovum. Consequently, damage to the embryo or fetus could occur before pregnancy was recognized.

Mr. GORE. Are you confident enough in animal extrapolation that you wouldn't mind being exposed to the TLV level of hexafluoroacetone on a daily basis?

Dr. KARRH. I am confident enough in it that I would not mind being exposed to it on a daily basis, that is correct. The extrapola

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tion of animal toxicity data to man is a standard toxicological method used to set acceptable workplace exposure levels.

The majority of the TLV's developed by the American Conference of Governmental Industrial Hygienists and incorporated into the OSHA law are based on animal data extrapolated to man. Mr. GORE. Back to the reproductive hazards to men, what concerns do you have about the possibility of birth defects caused by exposure of men to reproductive hazards?

Dr. KARRH. We have the same concerns that we have about the exposure of females that may cause them to have children with birth defects, or by the exposure of females who may be pregnant that would cause the infant to be born with a birth defect. It is no different than our concern over any other toxic potential of our workplace.

That is why we try to control our workplace exposures to the level that will prevent employees from suffering any adverse effect on any of their physiological functions.

Mr. GORE. And what do you do about that at Du Pont?

Dr. KARRH. I am not sure I understand.

Mr. GORE. To deal with those concerns?

Dr. KARRH. We set our exposure levels at a level where we will not cause these physiological effects in our employees and we meet those either by engineering controls, work practices, personal protective equipment, or a combination of these, for the adult male or the adult female.

Mr. GORE. That statement evidences a high degree of confidence in the knowledge that you have about the effects of these chemicals, whereas Dr. Hunt described massive uncertainty in this exact area. We just don't know.

Dr. KARRH. I don't think we are any more knowledgeable than Dr. Hunt, nor is our confidence level any greater perhaps than is Dr. Hunt's. We do extensive toxicological testing. We test new chemical substances in animals before we start putting them into the workplace and, based upon that, we do an assessment of the risk and the toxic potential. We also put in a safety factor from what we find out from the animal data and then decide what is acceptable exposure level for that particular chemical in the workplace.

Then we design our workplaces to meet that level by engineering controls, if at all possible, supplemented by work practices and administrative controls. There is a great deal of uncertainly but I don't think that we are unique in that.

We have a full toxicology laboratory which does nothing but animal testing to try to help us decide what are acceptable workplace exposure levels. The OSHA Act incorporated as law, some of these levels that were set by exactly the same methods that we are utilizing.

Mr. GORE. The uncertainty, itself, has legal implications. The company-and I invite your comment, Mr. Hapka, if you don't feel uncomfortable in addition to giving advice to Dr. Karrh-is it fair to assume that the legal exposure of a chemical company to a cause of action brought by a child with a birth defect is significantly greater where the alleged exposure occurred in utero than