Capacity of modified portable ladders

June 18, 1993
Mr. Richard O. Johnson
President
Communications Workers of America, Local 7200
[Recipient address omitted]
Dear Mr. Johnson:
This is in response to your letters of May 3 and May 11 requesting an interpretation of the Occupational Safety and Health Administration (OSHA) standards addressing the capacity of portable ladders. I apologize for this delay in responding to your inquiry.
As you know, OSHA requires extra-heavy duty type 1A metal or plastic ladders to be able to support at least 3.3 times the intended load. With regard to modifying a ladder to accommodate loads in excess of the manufacturer's rated capacity (e.g. by the installation of Safe-T-Legs), please be advised that OSHA would consider modified ladders to be in compliance with this requirement if a registered professional engineer has certified that the ladder, as modified, meets OSHA's 3.3 to 1 strength to intended load ratio requirement and the ladder is used in accordance with the certification.
Accordingly, OSHA would consider extra-heavy duty type 1A ladders equipped with Safe-T-Legs, as specified in the certified test results enclosed in your letter, to have a capacity of 360 pounds when the legs are properly installed. However, nothing in this letter should be interpreted to be an approval nor endorsement per se of the Safe-T-Legs product. The variable working conditions at jobsites and possible alterations or misapplication of an otherwise safe product could easily create a hazardous condition beyond the control of the manufacturer.
If we can be of any further assistance, please contact me or Mr. Dale Cavanaugh of my staff at (202) 219-8136.
Sincerely,
Roy F. Gurnham, P.E., Esq.
Director
Office of Construction and Maritime
Compliance Assistance

[Requester letters and related materials reproduced on OSHA page; omitted here.]