The requirement is that the light be “Listed”, but not necessarily “UL Listed”.
Listed means certified for use in pools or spas by a qualified testing laboratory.
The accepted standard is UL676.
So, any qualified testing laboratory should make sure that the lights at least meet that standard.
So, it’s a bit confusing since the standard is a UL created standard but the test can be carried out by any “qualified” testing laboratory.
If the light is sold for pool or spa use, it should be listed by a qualified testing laboratory and the manufacturer should specify which testing laboratory has certified the light.
www.osha.gov
The following is the complete list of test standards determined to be appropriate for use under OSHA's NRTL Program.
www.osha.gov
After certifying a product under the NRTL program,
the NRTL authorizes the manufacturer to apply a registered certification mark to the product.
This mark signifies that the NRTL tested and certified the product under the NRTL program, and that the product complies with the requirements of one or more appropriate product safety test standards.
Users of the product can generally rely on the mark as evidence that the product complies with applicable OSHA approval requirement(s) and is safe for use in the workplace.
www.osha.gov