The OSHA proposal released on Friday would require shipyards and construction companies that use coal slag to meet the same new maximum exposure limit as other industries. But it also proposes to exempt the two sectors from several so-called ancillary requirements, like medical monitoring of employees and other specific safety measures.

OSHA estimates that there are about 11,500 affected workers in the construction and maritime industries, compared with 50,000 workers in other industries covered by the regulation.

In the document, the agency said it was taking the step because further review indicated that the ancillary safety measures provided no additional benefits in the maritime and construction industries, which had adequate additional safeguards already in place, such as the use of protective gear.

The Abrasive Blasting Manufacturers Alliance, an industry group formed by companies that sell coal slag, including the Harsco Corporation, had argued there was no evidence linking its use to beryllium disease. Public records show that the group has spent at least $60,000 to lobby OSHA since January.

Beryllium or alloys that contain the mineral are used to make airplane parts, computer components and nuclear weapons. The metal can also cause disease at extremely low doses in the small percentage of people who, because of their genetic makeup, have a vulnerability to it.