The hearings will be July 16 in Washington, D.C.; July 20 in Illinois; and July 24 in California, with a goal of developing a universal definition of injuries caused by repetitive motion and stress. Chao will decide by September if she will pursue another government regulation or a voluntary policy.

"Guiding principles will provide a vital starting point for evaluating the issue and a point from which we can decide a final course of action," she said in a statement.

Ergonomics is the science of adapting working conditions to suit individual employees. Critics have complained that there is not enough scientific evidence to justify employer regulations that were issued late in the Clinton administration, but repealed in March by the Republican-controlled Congress. Since, Chao has been under pressure to say how she will address workplace injuries.

The hearings are intended to develop consensus on how the injuries occur and establish the federal government's role in identifying such injuries.

Also, the hearings will help fulfill Chao's pledge to conduct a "comprehensive review" of the issue. She promised that it was a priority, but until now had declined to set a timetable or discuss how she would proceed.

Her reluctance to answer such questions has earned her tough criticism at several congressional hearings, especially from Republican Sen. Arlen Specter (PA), who voted to repeal the regulations with the understanding that the administration would address the issue.

In Congress, bills have been introduced that would require the agency's Occupational Safety and Health Administration to issue a final rule within two years - over the objections of the White House and Labor Department.

President Bush signed a repeal of the regulations passed by Congress after a bitter legislative fight that pitted business against organized labor. Republicans led the charge with a little-used legislative maneuver that prevented lengthy debate and stalling tactics.

The rollback was a big blow to organized labor, which had fought for such protections for more than a decade. Labor argued that enough studies and hearings have been conducted that support the need for regulations.

The OSHA rules were issued late in the Clinton administration, and opponents complained that compliance was difficult because the rules were too costly and broad. Businesses estimated the price tag at $100 billion, though the government put the cost much lower.