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.

November 13, 1992

Ms. Patricia Falls
Firstline Safety Management, Inc.
Post Office Box 230
Lovettsville, Virginia 22080

Dear Ms. Falls:

This is a further response to your letter of September 14, addressed to Acting Assistant Secretary Dorothy Strunk, and your telephone conversation of November 2, with a member of my staff, in which you requested guidance on the outside storage and use of methyl ethyl ketone (MEK).

In your letter and during the telephone conversation you stated that the MEK is stored in several 55-gallon (208.2 liter [l]) drums, is transferred into five-gallon (18.9 l) containers, and is used to clean the hoses, pumps and nozzles of spray guns that are used to paint bridges. Since MEK is a Class I Flammable liquid, the use and storage requirements are found at 29 CFR 1926.152. Our answers to your questions follow.

Question 1: When transferring to a smaller container either by pouring or pumping, do the containers need to be grounded to prevent sparks?

Reply: Yes. The nozzle and the container must be electrically interconnected to each other to meet the bonding requirements of 1926.152(e)(2).

Question 2: If this material is stored in a fenced yard away from the work area, is its original D.O.T. - approved shipping container suitable?

Reply: Yes. The 55-gallon (208.2 l) containers of methyl ethyl ketone may be stored in their original D.O.T.- approved shipping containers. The amount stored in any one area shall not exceed 1100 gallons (4163.5 l), and shall meet the separation, diking and other applicable requirements of 1926.152.(c)(1) through (7).

Question 3: For storage in small containers (up to five gallons) (18.9 l) on the jobsite, is a safety can required?

Reply: Yes. 1926.152(a)(1) states that only approved metal safety cans shall be used for flammable liquids in quantities greater than one gallon (3.8 l).

Question 4: This material is used to run through spray guns to prevent paint from clogging the hoses, pump and nozzles. When in use, it must be in a five-gallon (18.9 l) plastic can with an opening large enough to get the spray pump and nozzle into it. The paint/MEK mixture is pumped back into a five-gallon (18.9 l) can and removed from the jobsite into a 55-gallon (208.2 l) drum for disposal later. Are we allowed to use this material in this manner?

Reply: Assuming the MEK manufacturer's warnings and recommendations are properly followed, and assuming that the MEK is stored in safety cans, as mentioned above, use of the MEK as outlined in your letter would not constitute a violation of OSHA standards.

If you need further assistance, please contact Roy Gurnham or Dale Cavanaugh in the Office of Construction and Maritime Compliance Assistance at (202) 219-8136.


Roger A. Clark,
Directorate of Compliance Programs