OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

August 31, 1984

W. Scott Railton
Reed, Smith, Shaw, and McClay
1150 Connecticut Avenue, N.W.
Washington, D.C. 20036

Dear Mr. Railton:

This is in response to your letter of June 19, concerning the applicability of the lead standard's prophylactic chelation prohibition (29 CFR 1910.1025(J)(4)) to the administration of a dietary zinc compound.

Based on your assertion that the compound contemplated for use blocks lead absorption, it appears that chelation is not involved. Therefore, a violation of 29 CFR 1910.1025(J)(4) would not exist.

Any experiment involving employees should be coordinated through the National Institute for Occupational Safety and Health (NIOSH). NIOSH assistance will help assure that proper controls and safeguards are employed (zinc reduces serum copper and may cause neutropenia).

Please feel free to contact us if further assistance is needed.


John B. Miles, Jr.
Directorate of Field Operations

June 19, 1984

David Smith, Director
Office of Health Compliance
Occupational Safety and
Health Administration
200 Constitution Avenue, N.W.
Room N3101
Washington, D.C. 20210

Dear Dave:

SERA, an acronym for the Smelter Environment Research Associates, has been approached by a medical researcher to fund a study to determine whether a dietary supplement using zinc might be effective as a means for blocking the absorption of lead.

In essence, the researcher states that his prior studies establish that dietary zinc is effective in blocking the absorption of copper. He claims that his treatment now provides a safe alternative for treating Wilson's disease. His expectation is that since lead is a divalent cation like copper and zinc, a dietary supplement of zinc would induce a high level of metallothionein which then should block further zinc uptake and lead uptake as well. He claims that zinc used as a dietary supplement is extremely safe, and he has Food and Drug Administration approval.

The researcher is Doctor George J. Brewer, Professor of Human Genetics and Internal Medicine of the School of Medicine, University of Michigan. Doctor Brewer would be assisted in this project by G. M. Hill, Ph.D., who is a post-doctoral fellow in the Department of Human Genetics at Michigan.

As proposed, the study would be conducted in two phases and would require that lead-exposed employees be involved as the study group. The first phase of the study would look to see if there is a negative correlation between zinc and lead. They theorize that persons having high zinc blood levels will, on average, have lower blood leads. The second phase of the study would involve administering supplemental zinc to lead-exposed volunteers to detremine whether the supplement will decrease the body burden of lead.

The question occurs, however, whether OSHA would consider an employer whose employees might volunteer to participate in the research as in violation of either 29 CFR 1910.1025(j)(4)(i) or 29 U.S.C. 654 (a)(1)? Secondly, if OSHA were to believe that a possible violation may exist, it would be of interest to know whether the Agency would agree to sanction research of this kind through the grant of an experimental variance.

We assume that our questions as well as the project itself might result in a need for additional information on your part. We shall be happy to arrange a meeting between you, other appropriate OSHA officials and Dr. Brewer as well as SERA representatives if that should be necessary.



By: W. Scott Railton