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 12, 1997

Mr. Walter Hyde
Hyde Consultants, Inc.
4106 Sherwood Lane
Houston, TX 77092

Dear Mr. Hyde:

This is in further response to your October 23 letter requesting clarification on whether the General Industry Standard requires an employer to use workplace electrical hazardous area classification drawings in the workplace. Your request was made referencing the Occupational Safety and Health Administration's (OSHA's) December 29, 1992 letter to Mr. R. J. Persac, Jr. This OSHA letter clarified that area classification drawings are not required as far as the electrical requirements of 29 CFR 1910.307 apply to petrochemical plants. Specifically, you asked the following questions:

Question 1:

Are there any General Industry standards that require an employer to compile, use and maintain current electrical hazardous area classification drawing(s) for facilities containing flammable or combustible materials?


Paragraph 1910.307 Hazardous (classified) locations which applies to workplace electrical utilization installations, does not specifically require an employer to compile, use, or maintain current, electrical hazardous area classification drawing. When applicable however, electrical classification information pertaining to process equipment may be required under paragraph 1910.119(d)(3)(i)(C). Please note that paragraph 1910.119(d) requires that process safety information be compiled by the employer. However, the method used to compile this information is not specified. This is consistence with the performance-oriented intent of the §1910.119 Process Safety Management Standard. An employer may choose to compile electrical classification information on drawings specifically dedicated for that purpose or by annotations to existing plans or drawings and by other methods or combination of methods including tables, or written commentary.

Question 2:

If an employer prepares electrical hazardous area classification drawings and issues them to employees with the intent of using them to consider the classification of an area (whether required by OSHA per question 1 or not), must the drawings: accurately represent the hazards involved, be updated to reflect process flammable or combustible material hazards and if required, is there a specific updating time limit?


An employer must maintain electrical hazardous area classification drawings current for use (to provide for the safety) of his or her employees.

We appreciate your interest in employee safety and health. If we can be of further assistance, please contact the Office of General Industry Compliance Assistance, Mr. Ronald J. Davies, telephone (202) 219-8031, extension 110.


John B. Miles, Jr., Director
Directorate of Compliance Programs