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.

April 17, 1991

The Honorable John McCain
United States Senate
Washington, D.C. 20510

Dear Senator McCain:

This is in further response to your letter of February 11, to the Occupational Safety and Health Administration (OSHA) concerning radon.

My letter of January 17, to Mr. Craig I. Willison of American Radon Corporation, related that an employer must conduct the survey described at 29 CFR 1910.1096(d)(1) of the ionizing radiation standard if he or she knows, or could have known with the exercise of reasonable diligence, of the existence of artificially enhanced concentrations of environmental radon-222 in the workplace. You seek a clarification of the term "reasonable diligence" in relation to knowledge of the existence of artificially enhanced concentrations of environmental radon-222. You described a theoretical situation in which ten percent of the structures surveyed in an Environmental Protection Agency (EPA) study area were found to exceed the radon standard, and inquired whether the exercise of "reasonable diligence" would lead an employer to conduct a survey to determine concentrations of radon in his or her workplace. Additionally, you inquired as to what incidence of radon found in surrounding buildings would trigger the exercise of "reasonable diligence" on the part of the employer, if ten percent was not the threshold requirement.

The answer to your question concerning the definition of "reasonable diligence" depends upon facts specific to each individual case. In this case, OSHA's definition would not be based solely on the percent of structures found to contain levels of radon exceeding the standard. However, given a situation in which an employer is provided with a copy of the referenced EPA report, it could be argued that knowledge of this incidence of radon, plus the fact that his workplace is within the confines of the geographical area surveyed, could give rise to a duty to test, or at a minimum, to make further inquiry. In addition, an employer could know of a potential hazard with the exercise of reasonable diligence if the media has reported excessive radon exposure in the area where the workplace is located.

We appreciate the opportunity to clarify this matter for you.

Sincerely,

 

Gerard F. Scannell
Assistant Secretary

 

March 5, 1991

The Honorable John McCain
United States Senate
Washington, D.C. 20510

Dear Senator McCain:

This is an interim response to your letter of February 11, to the Occupational Safety and Health Administration (OSHA) concerning radon.

In order to address your concerns fully, we are in the process of gathering information. We expect to provide you with a full response shortly.

Thank you for your patience.

Sincerely,

 

Gerard F. Scannell
Assistant Secretary

February 11, 1991

Mr. Gerald F. Scannell
Assistant Secretary
Suite S2315
United States Department of Labor
Occupational Safety and Health Administration
200 Constitution Avenue N.W.
Washington, D.C. 20210

Dear Mr. Scannell:

I'm writing on behalf of some of my constituents regarding interpretation of 29 CFR 1910.1096(d)(1) relative to OSHA's radon standards.

In your letter to Mr. Craig I. Willison of American Radon Corporation you stated that an employer must conduct a survey as specified in 29 CFR 1910.1096 if he "knows, or could have known with exercise of reasonable diligence of the existence of artificially enhanced concentrations of environmental radon-222 in its workplace". Specifically I have three questions that need to be addressed. 1) What is the definition of "reasonable diligence" within the context of 29 CFR 1910.1096? 2) If ten percent of the structures surveyed in an EPA study area are found to exceed the radon standard, does "reasonable diligence" require an employer to conduct a survey to determine concentrations of radon in his or her workplace? 3) If ten percent is not the threshold requirement, what specific incidence of radon would require an employer to test his or her workplace for radon levels to demonstrate "reasonable diligence" according to OSHA standards?

I would appreciate it if you could send your response to the attention of John Raidt in my Washington office, 111 Russell Senate Office Building, Washington, D.C. 20510. Thanks in advance for your assistance in interpreting these regulations.

Sincerely,

 

John McCain
United States Senator