The Occupational Safety and Health Administration has proposed to amend its existing standards for occupational exposure to respirable crystalline silica, which are very small particles - at least 100 times smaller than ordinary sand on beaches and playgrounds – and are created during work operations involving stone, rock, concrete, brick, block, mortar, and industrial sand.

The public comment period before OSHA's proposed rulemaking on occupational exposure to crystalline silica has been extended 47 days.

This extension gives stakeholders in the matter now until Jan. 27, 2014 to submit written comments and testimony regarding the proposed rule and supporting analyses. The previous deadline was Dec. 11, 2013.

OSHA also extended the deadline to submit notices of intention to appear at its informal public hearings until this Thursday, Dec. 12, 2013. Public hearings are scheduled to begin on March 18, 2014. The number of parties who request to appear will determine the duration of the hearings, which are expected to continue for several weeks.

"We strongly encourage the public to assist in the process of developing a final rule by submitting written comments and participating in public hearings," said assistant secretary of labor for occupational safety and health Dr. David Michaels. "We especially hope to hear from employers, workers and public health professionals who have experience in successfully protecting workers from silica-related diseases. We are extending the comment period to ensure we hear from all stakeholders who wish to participate."

The extended comment period and public hearings will be followed with a post-hearing comment period. Members of the public who filed a timely written notice of intention to appear will be able to submit post-hearing comments to the docket.