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.

February 1, 1982

Mr. William C. Pohl
Quality Assurance Manager
Construction Systems Division
3333 North First Street
San Jose, California 95134

Dear Mr. Pohl:

This is in response to your letter of November 17, concerning the OSHA construction industry standard for laser use (29 CFR 1926.54).

As you have indicated, the standard takes no cognizance of different classes of lasers. All of the provisions of the standard technically apply to all uses of lasers in the construction industry. However, Class I lasers are defined to present no hazard. Therefore, violations of those paragraphs which should really only apply to higher class lasers should, in the case of Class I lasers, be regarded as "de minimums," which means there would be no citation, no penalty, and no compliance date. Although the language of the regulation is violated, employees are not being subjected to a hazard. (See section 9(a) of the Occupational Safety and Health Act of 1970 enclosed.)

Since your Model EL-1 electronic level is a Class I laser product in accordance with 21 CFR 1040.10, OSHA must generally regard nominal violations of 1926.54 associated with the use of this product to be only "de minimis." However, the specific exposure limits of paragraph (j) of the OSHA standard do not depend on the laser's class and will continue to have full effect. The OSHA standard is more restrictive than the Bureau of Radiological Health (BRH) standard because the allowable power density for BRH-Class I visible lasers is higher than the OSHA limit of 1 microwatt per square centimeter (designated for "direct staring") over the whole BRH standard's time interval of 1 to 10,000 seconds, except at the upper interval limit of 10,000 seconds. Since the term "direct staring" could easily be interpreted to apply to viewing times much less than 10,000 seconds (166 minutes), in such cases, the OSHA standard would be exceeded by a Class I product. On the other hand, the OSHA limit of 1 milliwatt per square centimeter for "incidental viewing" equals the BRH Class I limit for a 10-second viewing time. Therefore, for "incidental viewing" times of less than 10 seconds, the OSHA standard is more restrictive, and incidental viewing normally implies viewing times of less than 10 seconds. In each case, these comparisons have used the limiting energy of 3.9 millijoules from the BRH standard, Table I-A. Violations of the exposure limits of paragraph (j) of the OSHA standard would mean that simultaneous violations of other parts of the standard could not be regarded as "de minimis."

It apparently remains to be determined whether an exposure above one microwatt per square centimeter for, for example, five minutes is properly either a hazard to a person's eyes or legitimately regarded as Class I, as it is defined. We hope to resolve this discrepancy between the BRH and OSHA standards in the near future.

Using the values you specified over the telephone of one milliwatt beam power over a three-quarter inch beam diameter, your Model EL-1 would produce a power density of only .35 milliwatt per square centimeter for "incidental viewing." Therefore, according to the OSHA standard, the laser is not hazardous even without any protection. As a result, the other provisions of 29 CFR 1926.54 cannot serve to protect anyone from a hazard and, therefore, any violations of requirements of those paragraphs would be regarded as "de minimis" violations. Please note that such a finding is not the same, legally or technically, as a citation from OSHA for failure to comply with the regulations. Citations are given for subjecting employees to risk through failure to comply with the regulations. A "de minimis" notice is a finding by OSHA that despite the language of the regulation, employees are not being put at risk.

A copy of this letter will be sent to our compliance officers so that they may be apprised of this situation. I trust that this information adequately answers your concerns. If you have any further questions, please feel free to contact us again.


John Martonik
Deputy Director
Health Standards Programs