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.

September 4, 1985

Mr. Ramon A. Napal
Vice President, Human Resources
Carlisle Syntech Systems
Post Office Box 7000
Carlisle, Pennsylvania 17013

Dear Mr. Napal:

Thank you for your letter of July 26 regarding the hazard Communication Standard (HCS) (29 CFR 1910.1200).

A telephone number is required on material safety data sheets, not labels. The purpose of the number is to ensure that someone can "provide additional information on the hazardous chemical and appropriate emergency procedures, if necessary." The standard does not explicitly state that the telephone number must be answered on a twenty-four hour basis. It appears that some judgment must be made based upon the probable use of your products, and the potential for the occurrence of emergency situations that would require additional information. Many firms that produce highly toxic materials that are likely to be used by other employers during three-shift operations do provide twenty-four hour coverage of their emergency telephone numbers. Producers of mildly toxic materials, which are used in operations that proceed during normal working hours, would be less likely to have such coverage.

Since the HCS is a performance standard, a determination as to what is appropriate in your situation must be made by your firm. We hope this information is helpful to you. If we can be of further assistance, please do not hesitate to contact us.


Jennifer C. Silk
Health Scientist
Health Standards Programs

July 26, 1985

OSHA Administrator
Ms. Jennifer Silk
Room N3663
200 Constitution Avenue NW
Washington, D. C. 20210

Dear Ms. Silk,

This letter is to request an official interpretation of the provision of the Right-To-Know Law that deals with labeling of products and information provided on Material Safety Data Sheets.

As you know, the Right-To-Know law requires both labels and MSDSs to list a telephone number. The question I am asking is - a twenty-four hour a day basis: We have made several phone calls, both to your office and to regional offices and have been told telephonically that the telephone does not have to be manned twenty-rour hours a day because the law does not specify such a requirement. We would appreciate, however, a written confirmation of that fact.


Vice President
Human Resources

Carlisle SynTec Systems
Division of Carlisle Corporation
P.O. Box 7000
Carlisle, PA 17013