WASHINGTON — The Bush administration is proposing that workplace hazard standards be subject to more public and expert scrutiny before being adopted. Critics say the proposals could make it harder to limit worker exposure to carcinogens and other toxic materials.

The Labor Department proposal to be posted on the Federal Register Web site today would require its agencies to seek additional public input and scientific data on workplace health hazards prior to issuing a rules change.

The department said this "Advance Notice of Proposed Rulemaking" would ensure that it was "casting a wide net for the best available data" before moving forward with health rulemaking.

The proposal "lays out in clear terms the process the department is going to follow" to obtain the best scientific data, Leon R. Sequeira, the Labor Department's assistant secretary for policy, said in an interview with The Associated Press. "We think this is a good compilation of best practices for health standards and that's why we are proposing it."

The department also proposes the electronic posting of all rulemaking information.

Critics argued that there is already ample opportunity in the rulemaking process for public and expert comment, and accused the Bush administration, with its history of differences with worker-rights groups, of taking 11th-hour steps to slow down the issuance of new health rules that industries say are overly onerous.

"They are spending their last months making it more difficult to put needed protections for workers in place in the future," said Peg Seminario, safety and health director for the AFL-CIO.

The Advance Notice process is not new, but the proposal would make it mandatory for health rulemaking.

Dr. Celeste Monforton of the George Washington University department of environmental and occupational health said the process can be of benefit when there is an emerging health hazard.

"But when you have a well-recognized hazard like coal mine dust," she said, "the only thing it gets you is additional years of rulemaking and that translates into delayed protection."

She said it could add two or three years to the eight years it might already take the Occupational Safety and Health Administration to finalize a rule. "That's two to three additional years of exposure," she said.

The Labor Department emphasized that the proposal is not health rulemaking, does not weaken any health standard and does not dictate the outcome of risk assessments. It also denied that the proposal would delay the implementation of new standards or substitute the judgment of political appointees for agency career professionals in assessing risks.

Claims that the administration is adding a new layer of bureaucracy to obstruct the implementation of new health and safety rules "are flat-out false," Sequeira said.

He said the department also decided on a 30-day public comment period although, since the proposal deals with internal department practices, no comment period is required. He said that should answer critics who say the department purposefully withheld information on the proposal as it was being drafted.

Rep. George Miller, D-Calif., and Sen. Edward Kennedy, D-Mass., chairmen of the House and Senate labor committees, last month wrote Labor Secretary Elaine Chao accusing the department of trying "to slip through a rule that may have a profound negative impact on the health and safety of American workers."

Miller, in a statement Wednesday, said that for nearly eight years the Bush administration has failed to respond to the health and safety threats faced by workers. "But now they will stop at nothing to rush through significant regulatory changes that are detrimental to average Americans." He has introduced legislation to stop implementation of the proposal.