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 15, 1990

Ms. Julie A. Emmerich
Suite 400
Chouteau Center
133 South Eleventh Street
St. Louis, Missouri 63102

Dear Ms. Emmerich:

This is in response to your letter of August 1, addressed to Ms. Cynthia Wolfe, Assistant Regional Administrator for Technical Support, of the Occupational Safety and Health Administration (OSHA) Regional office in Atlanta, Georgia. You wrote your letter on behalf of your client, Purina Mills, Inc., as a result of an OSHA inspection at one of their facilities. Your letter was subsequently forwarded to the National Office for a response. We apologize for the delay in our response.

Your letter focused on two issues concerning the OSHA standard at 29 CFR 1910.272(g)(4), for which one of your client's facilities located in Montgomery, Alabama, was cited for violation of the standard. The issues of your concern are:

1) The type and quantity of rescue equipment that is required, that is, how many hoists, boatswain chairs, etc., must be kept available for rescue, and what factors should be considered in determining the location where such equipment shall be kept.

2) Whether a provision for outside rescue teams can be used in conjunction with an in-house rescue plan. If so, how can the rescue plan be tailored so that it specifies when the outside rescue team should be relied upon.

In response to the first issue, an employee waiting outside a bin, silo, or tank as an observer, for the purpose of rescue operation, must be provided with a protection equivalent to the protection provided to the employee entering the bin, silo, or tank. Therefore, at a minimum, each establishment must have one set of the following equipment available in the immediate vicinity of the observer:

1) A hoist; and

2) A two-way radio (intrinsically safe), if use of voice or signal communication is not feasible; and

3) A body harness attached to an independent lifeline, or a boatswain chair meeting the requirements contained in subpart D of OSHA general industry 1910 standards. If a boatswain chair is provided to the observer for rescue operation, the observer must then be protected by requiring him or her to wear a safety belt attached to a lifeline. This lifeline must be securely attached to an independent structure other than the members or support of the scaffold.

4) A self contained breathing apparatus or an airline respirator, if the atmosphere within silo, bin, or tank has not been tested, or has been tested and determined to endanger the life and health of the observer, prior to observer's entry.

With respect to your second issue, OSHA does not prohibit the use of an outside rescue team in conjunction with in-house rescue plan. However, use of additional outside rescue teams would be beneficial, primarily if the teams can arrive immediately after an incident requiring a rescue operation occurs. Therefore, if a company chooses to use outside rescue team in conjunction with the in-house rescue team, the employee acting as observer must not only be trained to notify the plant personnel for additional assistance, but also be trained to notify the outside rescue team to obtain additional assistance.

Thank you for your interest in safety and health. If we may be of further assistance, please contact us.


Patricia K. Clark, Director
Directorate of Compliance Programs