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.

December 1, 1989

The Honorable John Heinz
United States Senator
9456 Federal Building
600 Arch Street
Philadelphia, Pennsylvania 19106

Dear Senator Heinz:

Thank you for your inquiry of August 23, on behalf of your constituent, Mr. James D. Topf of Topf Enterprises in Tyrone, Pennsylvania.

In your letter you described Mr. Topf's difficulty in marketing his temperature control devices for use in the grain elevator industry, due to OSHA's requirement that such devices be certified by a Nationally Recognized Testing Laboratory (NRTL). You stated that the charge for certification at such laboratories is more than $12,000.

As you may recall, the grain elevator standards were developed to eliminate the disastrous occurrences of past years. The standards require that these critical devices be certified by a NRTL to assure that they do not become ignition sources in the grain elevator environment. NRTL's are required to provide for continuous monitoring of certified products throughout their production life.

OSHA cannot accept a Mine Safety and Health Administration (MSHA) certification as equivalent to the certification required under the OSHA standard. Such a determination is not an alternative because MSHA did not certify that Mr. Topf's devices are intrinsically safe in a grain environment nor does MSHA certification provide for continuous monitoring of certified products.

Although we are sympathetic to Mr. Topf's situation, we have a responsibility to the workers in the grain elevator industry. OSHA cannot permit employers to install devices in critical and hazardous locations unless they are certified by a NRTL for the specific service in which they are to be used. Therefore, if Mr. Topf's devices are not certified by a NRTL, employers who might install them would be in violation of the standards.

If we may be of further assistance, please contact us.


G.F. Scannell
Assistant Secretary