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 23, 1995

Mr. Mark Arriens CleanHarbors Environmental Services Companies 1200 Crown Colony Drive P.O. Box 9137 Quincy, MA 02269

Dear Mr. Arriens:

This is in further response to your letter requesting guidance in determining whether certain spaces with which your company has to address routinely would be considered confined spaces by applying the Permit-Required Confined Spaces (PRCS) standard's definition. Please accept our apology for the delay in this response.

You also requested, that for every question, the Occupational Safety and Health Administration (OSHA) consider situations where materials may be present in the space and where the spaces are empty. The issue of whether the containers listed below are empty or contain a material is not a determining factor in a space's classification as a confined space, although it is relevant for determining if it is a permit-required space. Since the contents of these containers can vary greatly, we will only address whether these spaces are confined spaces when empty.

We have restated your original question in our response for ease of reference.

Question 1. Roll-Off Container: This equipment consists of a rectangular open-topped body (typically 20-25 ft. Length x 7-8 ft. Width and 4-5 ft. Depth), steel construction, typically used for storage of waste, debris, material, etc. and varies in size--20/30/40 cubic yard capacity. Two configurations are used: Doors at one end and no doors.

Response. A open top roll-off refuse container would be considered a confined space when the second element in the standard's definition ("has limited or restricted means for entry and exit") would apply. When the doors are in a secured open position, the containers described above would not be considered a confined space either on or off the transport vehicle.

For those open top roll-off containers that do not have doors, the use of a temporary stair meeting the specifications for a fixed industrial stair, securely installed, would provide an unrestricted means of entry or exit.

Question 2 Dump Truck Bed: The Beds vary in depth from 4-5 feet. However, as material (such as soil) is loaded, the depth diminishes. The rear door swings up and can be placed in this position during entry.

Response. The bed of a dump truck or trailer is similar to the roll-off container and as such would be classified as a confined space if it so configured that the second element in the standard's definition (Has limited or restricted means for entry or exit) would apply. The question we believe, is whether a 4 to 5 foot tailgate door with the hinge point at the top of the side rails, in a raised position, constitutes a restriction to entry or exit. We believe that it does constitute a restriction unless it is secured in the open position.

Although certain aspects of work practice are not at issue in this letter, we believe a note of caution is in order concerning your statement that the door swings up and can be placed in this position during entry. A top hinged door, which can swing down and strike an employee causing injury must be positively secured to prevent the door from accidentally closing.

Question 3 Truck Trailer: This is a typical tractor/trailer configuration: The trailer used by our company is 40 ft. length x 8 ft. Width x 8 ft. Height and is equipped with two doors at the rear of the unit.

Response. A typical tractor/trailer of the type described above with the doors in the open position would not be considered a confined space. When the doors are in the (secured) closed position, it would be considered a confined space since the doors of the trailer typically cannot be opened from the inside.

Question 4 High Velocity Vacuum: Trade names: Vactor, Guzzler, Supersucker (See attached literature). Entry into the tank unit. The door is located at the rear of the truck, and swings up from the bottom, and is secured in this position during entry.

Response. Based on the literature provided, it appears that the baghouse would be considered a confined space. The tank compartment would also be a confined space if the entry/exit point is restrictive.

If you have further questions on this response please contact Mr. Don Kallstrom in the Office of General Industry Compliance Assistance (202)219-8031. Again please accept our apology for the delay.


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