U.S. steelmakers want the EPA to tighten a draft mercury reporting rule to help them keep the toxic metal out of their supply chains.

An Environmental Protection Agency proposal would deprive steel makers of information they need to prevent mercury-containing switches, lamps, batteries, and other equipment from getting into their scrap recycling feedstocks, Eric Stuart, vice president for environment and energy at the Steel Manufacturers Association, told Bloomberg Environment.

Collecting more information could help steel makers prevent mercury from...