More than 300 scientists, doctors and workplace safety experts are asking President Obama to step in to speed much-needed protections against worker exposure to crystalline silica.

They signed a letter to the president today, urging him to direct the White House Office of Management and Budget (OMB) to complete its review of a proposed rule from the Occupational Safety and Health Administration (OSHA) on silica dust.

Some 1.7 million workers are exposed to crystalline silica, which kills some 200 workers each year and causes new cases of silicosis in as many as 7,300 workers, mostly in the construction field. Silicosis is incurable but preventable.

Says Leonard Serafin, a former railroad worker from California:

Every day I struggle to do activities because of my condition. I want to see that other people are protected from this dust—it’s not fair to expose people to something this dangerous when they can be protected.

OMB should have completed its review of the proposed rules within 90 days, but has delayed for nearly a year. The letter notes that OMB staff has hosted at least nine private meetings on the rules, most of which involved representatives of companies with a direct financial stake in their outcome.

Stronger worker protections from silica  are a priority for the AFL-CIO, the Building and Construction Trades Department and many unions, who have been pushing for improved standards for years. This current rule has been in development for 14 years, according to a release from the Union of Concerned Scientists. Every day the rules are delayed, more workers are at risk.

Read more in this report from Huffington Post.