ANSI/ITSDF B56.1 is the US voluntary consensus safety standard for low lift and high lift trucks, covering design and construction requirements for manufacturers and safe operation and maintenance practices for users.
B56.1 is published by the Industrial Truck Standards Development Foundation (ITSDF) as an American National Standard. It belongs to the B56 family, which also includes B56.5 for driverless and guided industrial vehicles and separate volumes for other truck types such as rough terrain trucks. The standard has a part for users, covering operator qualification, operating practices and maintenance, and a part for manufacturers, covering stability, brakes, overhead guards and markings.
OSHA 1910.178(a)(2) requires trucks acquired after February 15, 1972 to meet the design and construction requirements of ANSI B56.1-1969. Later editions are not incorporated into the OSHA rule, but consensus standards can be used as evidence of recognized hazards and feasible controls, and manufacturers build to the current edition. The ANSI B56.1 vs OSHA comparison explains where the two differ. This is a summary, not legal advice.