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.

February 22, 1995

The Honorable Richard E. Neal
U.S. House of Representatives
1550 Maine Street Federal Building
Springfield, MA 01103

Dear Congressman Neal:

This is in response to your July 25, 1994 and December 7, 1994 letters regarding the request for assistance by Ms. Catherine Benjamin, Safety Coordinator for the FLEXcon Company, Inc. In the FLEXcon letter of July 15, 1994 enclosed with your letter, Ms. Benjamin requested an interpretation and clarification of the Process Safety Management (PSM) of Highly Hazardous Chemicals (HHCs) standard, 29 CFR 1910.119 as it may apply to processes containing HHCs at one of her company's work sites.

As noted in our August 19, 1994 interim response to you, further research was required to provide the response which follows. This research included additional information gathering on the aforementioned work site. Both oral and documented information was obtained by way of several telephone communications between Mr. Darwin Irish of FLEXcon and Mr. Ronald Davies of my staff. The work site scenario described in the aforementioned FLEXcon letter is reiterated below. Our PSM interpretation and clarification comments follow. Please accept our apology for the delay in responding.


At one of FLEXcon's work sites is stored in excess of 10,000 pounds (4535.9 kg) of flammable liquid adhesive in six individual atmospheric bulk tanks each of which have an 8,000 gallon (30,820 liter) capacity. These adhesives are kept below their normal boiling point without the benefit of chilling or refrigeration. They are piped from a bulk storage interior room to one manufacturing plant and into a ventilated dispensing booth. Employees dispense the adhesive into 55 gallon (208.17 liter) drums. Operators then transfer the drums to a mixing area where a small amount of additive or solvent may be added to the adhesive mixture prior to transferring the mixture to a coating machine. Also, the adhesive may be transferred undiluted to one of three machines for direct application to the product.

One of the six bulk tanks is interconnected by piping to a manifold in a fire-protected booth which serves as the pumping or feed station for one of the three machines in this location. The operator must hold a dispensing switch down to fill a 55 gallon drum. After the drum is filled, the operator inserts a pump into the drum which feeds the coating pan on the coating machine. In this one instance the drum is not transported to another location unless the adhesive was dispensed for use on another machine. The drum serves as a storage or holding container. If an additive is needed, the drum is transferred to a mixing area and then returned to the fire protected booth to be pumped to the coating pan.

The scenario described above includes a process which is considered covered by the PSM standard as determined by the following interpretation and clarification. Please be advised that compliance with the PSM standard is determined on a work site by work site basis. By the definition of "process", the eight flammable liquid adhesive storage tanks in the interior tank room, the flammable liquid adhesives in the 55 gallon drums at the mixing stations and in the production area outside of the drum storage room, and the flammable liquid adhesives in the coating machines are considered contained in a single process. Depicted in the floor plan of the facility containing FLEXcon's process are three mixing stations, one of which is in a fire-protected booth, in the production area. The tanks and containers are connected by piping or unconnected and in close proximity to each other such that collectively, the flammable liquid adhesives in these tanks and containers could be involved in a potential release. See the preamble discussion in the middle column of page 6372 of the PSM Final Rule (copy enclosed) for further clarification of the basis for this provision of the standard.

Please note that the term "interconnected" includes on-site movement of flammable liquid adhesives from the storage tanks by way of piping which is not directly connected to but dispenses by way of a control valve directly into 55 gallon drums. Some of the 55 gallon drums are used for mixing which is considered a handling activity. Handling and on-site movement activities include filling of the coating pans of the coating machines either remotely by pumping the flammable liquid adhesives from the 55 gallon drums by way of interconnected piping, or locally by transporting the 55 gallon drum, to the coating machines. Flammable liquid adhesives dispensed by the coating machines onto labels is considered a manufacturing activity. In summary, the FLEXcon process includes on-site movement, handling, blending and manufacturing activities, which cancels the exception at 1910.119(a)(1)(ii)(B) which allows only storage and associated transfer as excepted activities.

FLEXcon Company, Inc. provided additional information including the aforementioned floor plan in a follow-up letter (enclosed) dated September 8, 1994 to their letter of July 19, 1994. This floor plan depicts the piping which interconnects the flammable liquid adhesive storage tanks (located in an inside storage room) and the manifolds (located at the mixing stations in the production area) passing through an adjacent inside storage room used to store flammable liquids adhesives in 55 gallon drums. Such a piping arrangement would cause this 55 gallon drum storage of flammable liquid adhesives to be part of the aforementioned covered process. Please be advised that 29 CFR 1910.106-Flammable and combustible liquids standard applies to the FLEXcon facility depicted on the floor plan. Specifically Section 1910.106(e) applies to this FLEXcon facility which is considered an industrial plant at which flammable and combustible liquids are stored, handled and used.

In the FLEXcon letter of July 15, 1994, Ms. Benjamin stated that "Companies dealing with any of more than 130 specific toxic and reactive chemicals in listed quantities, and flammable liquids and gases in quantities of 10,000 pounds or greater, are subject to PSM with one exception." Ms. Benjamin identified the flammable liquids stored in atmospheric tanks exception of paragraph 1910.119(a)(1)(ii)(B). Please note that the PSM standard includes other exceptions covered by paragraphs 1910.119(a)(1)(ii)(A) and (a)(2)(i) through (iii).

We appreciate your interest in employee safety and health. If we can be of further assistance, please contact Mr. Ronald J. Davies of my staff on 202-219-8031, extension 110.


Joseph A. Dear Assistant Secretary