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 http://www.osha.gov.

April 7, 1980

Dr. Sidney Lerner
University of Cincinnati Medical Center
College of Medicine
231 Bethesda Avenue
Cincinnati, Ohio 45267

Dear Dr. Lerner:

This is in response to your inquiry addressed to Mr. Gail Brinkerhoff of my staff regarding the Occupational Safety and Health Administration's interpretation of specific sections of the arsenic standard.

The Arsenic Standard under 29 CFR 1910.1018(n)(1)(ii) requires "that all medical examinations and procedures be performed by or under the supervision of a licensed physician." The physician interpreting the chest X-rays must be capable of giving them a rating in accordance with the criteria of the International Labor Office UICC/Cincinnati (ILO-U/C), as required under 29 CFR 1910.1018(n)(2)(ii)(A).

The set of standard films illustrating the ILO-U/C Classification of Radiographs of Pneumoconioses is being revised. The new set of films will be available soon. For further information you may contact:

[This document was edited on 8/12/99 to strike information that no longer reflects current OSHA policy.]

Washington Branch
International Labor Office
1750 New York Avenue, N.W.
Washington, D.C. 20006

Telephone: (202) 634-6335

Even though all licensed physicians receive some training in pulmonary medicine, as you stated, such training would not by itself be sufficient to enable any physician to make a full determination of an employee's ability to wear a respirator. Any licensed physician with such training could make an initial determination as to whether an employee could wear a respirator. Anemployee who experiences difficulty in breathing during fit testing or use, however, would have to be examined by a physician with specific training in pulmonary medicine. Minimum physician training for this purpose would be at least one year of subspecialty training in pulmonary medicine, or board eligibility in internal medicine.

29 CFR 1910.1018(h)(3)(iii) requires employers with more than 20 employees using negative pressure types of respirators to perform fit testing. This includes all self- contained breathing apparatus operating in the demand mode, as well as nonpowered, air-purifying respirators. This requirement is being enforced by OSHA.

[This document was edited on 8/12/99 to strike information that no longer reflects current OSHA policy.]

As regards your question about the relationship between quantitative fit testing and the selection of respirators prescribed in Tables I and II, I offer the following explanation.

Tables I and II are used for the selection of respirators based upon airborne concentration levels. For example, if an employee exposed to arsenic trioxide is exposed to a maximum concentration of 400 micrograms of arsenic per cubic meter of air as an 8-hour, time-weighted average, then any respirator in Table I other than one of those across from item (v) may be selected, provided the respirator will afford the minimum protection factor required.

In this example, the minimum protection factor required is 400 divided by the permissible exposure limit = 400/10 = 40. The quantitative fit test is used to determine if the respirator selected actually provides the required protection factor. If the respirator does not do this, then another brand or type of respirator that will do so must be selected.

Quantitative fit testing results may be substituted for the respirator selection logic in Table I. This is so if:







  1. The need for eye and face protection or considerations other than the protection factor do not militate against the use of the respirator.
  2. The testing is competently and accurately performed.
  3. The respirator provides an adequate protection factor without being uncomfortably tight.

Quantitative fit test results shall not be substituted for the respirator selection logic in Table II. This is because Table II pertains to the selection of respirators which will provide protection from inorganic arsenicals in the gaseous state. Respirators with filter cartridges have limitations for purifying the air of gases and vapors due to "breakthrough" of the filter media. Thus, although a quantitative fit test result may indicate that a respirator with a cartridge filter has a very high protection factor, the respirator may nonetheless not provide adequate protection at a high concentration because of early breakthrough of the filter by the gas or vapor.

Respirators must be selected from Table II, where respirator protection is required against any of the substances included or specified in the list that follows:















  1. Arsenic trichloride
  2. Arsenic trifluoride
  3. Arsenic pentafluoride
  4. Arsenic tribromide
  5. Arsenic triiodine
  6. Arsenic monophosphide
  7. Any other arsenic-containing, inorganic compound that has an equilibrium vapor concentration (as arsenic) in excess of 1 microgram per cubic meter at 30o C.(This is an administrative interpretation.)

29 CFR 1910.1018 does not address the issues of whether and how much workers should be paid for taking showers required by the standard. It is our view that the standard should not be interpreted to create a right for payment. However, the Fair Labor Standards Act (FLSA) appears to pertain. With one or two exceptions it interprets shower times as "hours worked." (29 U.S.C. SS 206, 207, 203(o), Steiner v. Mitchell, 350 U.S. 247 (1955).) The exceptions apply to situations where "time spent in changing clothes or washing at the beginning or end of each workday was excluded . . . by the express terms of or by custom or practice under a bona fide collective bargaining agreement applicable to the particular employee." (29 U.S.C. S203(o), 29 CFR S785.26, Nardone v. General Motors, Inc., 207F Supp. 336 (D.C. N.J. 1962).) The FLSA may not, however, require any more than minimum wage to be paid.

Making training materials available to the employee for the employee to take home to read would be adequate to comply with [29 CFR 1910.1018(o)(2)] This is not to be confused with a training program which must be presented by formal instruction with all items of 29 CFR 1910.1018(o)(1)(ii)(A-F) covered.

I hope your questions have been sufficiently answered. If I can be of further assistance, please feel free to contact me.


Grover C. Wrenn Director,
Federal Compliance and State Programs