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.

October 25, 1986

Leo J. Sioris, Pharm.D.
Assistant Managing Director
Minnesota Regional Poison Center
640 Jackson Street
St. Paul, Minnesota 55101

Dear Mr. Sioris:

This is in response to your letter of June 9, 1986 concerning the availability of emergency information under the Hazard Communication Standard (HCS), reference 29 CFR 1910.1200.

Your question and our response is as follows:


Do emergency information lines have to be operated 24 hours per day, or for some other specified time period?


The HCS is primarily written in performance language. Paragraph (g)(2)(xii) of 29 CFR 1910.1200 does not specify hours of operation for emergency information lines.

The Occupational Safety and Health Administration's policy is to resist providing specifications that would erode the intended flexibility of performance standards. The Agency therefore, only provides guidelines to assist employers in fulfilling their responsibilities under the standard.

Chemical manufacturers should consider the following criteria in deciding the hour of operation of their emergency telephone line:

1) The completeness of the material safety data sheet for products

2) The toxicity/physical hazards of chemicals

3) The frequency the chemicals will be used and the immediacy of information needs based on all the above

4) Availability of information through other sources

If for example a manufacturer feels that their material safety data sheets are comprehensive and the products present little risk then the emergency number need only be open during normal work hours.

In summary, hours of emergency line operation must be decided individually by each chemical manufacturer.

Please feel free to contact us again if further assistance is needed.


John B. Miles, Jr., Director
Directorate of Field Operations

September 10, 1986

Mr. Roy Gibbs
Director of Field Operations
Department of OSHA
Washington, D.C. 20210

Dear Mr. Gibbs,

We are enclosing a copy of our letter mailed to Ms. Jennifer Silk on June 9, 1986.

In a follow-up telephone conversation on September 3, 1986, we were informed that she had forwarded our letter to your department for proper interpretation. We would appreciate receiving your clarification of this particular paragraph.


Leo J. Sioris, Pharm.D.
Assistant Managing Director

June 9, 1986

Ms. Jennifer Silk
Department of OSHA
200 Constitution Ave. NW
Washington, DC 20210

Ref: Hazard Communication Standard (g) Material Safety Data Sheets

(xii) The name, address and telephone number of the chemical manufacturer, importer, employer or other responsible party preparing or distributing the material safety data sheet, who can provide additional information on the hazardous chemical and appropriate emergency procedures, if necessary.

Dear Ms. Silk:

We would appreciate clarification relative to the time element for answering emergency procedures by telephone for manufacturers, importers, employer or other responsible party preparing or distributing the MSDS.

We are of the opinion that due to the various time zones in the U.S. and the fact that many hazardous chemicals are used by employees on nite-shifts, that telephone calls should be answered on a 24-hour-a-day basis to furnish appropriate emergency information caused by a hazardous chemical exposure. Many manufacturers are assuming compliance by answering these phones during the usual working day (8 a.m. - 5 p.m.). We would appreciate a written response from OSHA regarding this matter.

Thank you for your time.


Leo J. Sibris, Pharm.D.
Assistant Managing Director