Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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

July 20, 1990

Donald W. Johnson
Safety Director
McLean Construction Company
6700 Curtis Court
Glen Burnie, Maryland 21061-6480

Dear Mr. Johnson,

his is in response to your request for a temporary variance and correspondence with Jim Concannon, Office of Variance Determination to delay the effective date of the anti-two-blocking standard (1926.550(g)).

As you know the final rule regarding crane or derrick suspended personnel platforms was published August 2, 1988, with an original effective date of October 3, 1988. Unfortunately, anti-two-blocking devices were not as readily available from manufacturers as had been anticipated, and it was not the Occupational Safety and Health Administration's (OSHA) intent to enforce a standard that could not be reasonably complied with. Therefore, on June 26, 1989, OSHA issued interim enforcement guidance to the field and delayed the effective compliance date to December 31, 1989, to allow employers additional time for delivery and installation of anti-two blocking devices.

The preamble to the final rule explains that the record supports OSHA's determination that hoisting a suspended personnel platform with a crane or derrick constitutes a significant hazard to hoisted employees and that it is prohibited unless there is no feasible safe alternative. The preamble further states that cranes and derricks are not manufactured for use as personnel hoists, thus supporting the claim that some cranes cannot be retrofitted with two-block-devices. As indicated by the Summary of the Regulatory impact Analysis (53 FR 29139), OSHA is aware that "some cranes, especially older mechanical ones, would require considerable modification in order to comply with the standard". The Agency has anticipated that some of those older cranes would be to difficult or expensive to retrofit. Recognizing this fact and the general prohibition against hoisting personnel with cranes or derricks, it would [not] be appropriate for OSHA to make special allowances or approve the use of any equipment or procedures that cannot comply with the current requirements of the standard. It is the responsibility of the employer, who determines that the use of a personnel platform is the only safe method available, to provide equipment that complies with all elements of the regulations. If a particular lattice boom crane cannot be adapted to use anti-two-blocking devices, it shall not be used to hoist personnel.


Gerald P. Reidy, Director
Office of Construction and Maritime
Compliance Assistance

[Corrected 09/20/2006]