This is from Bryan Caplan:
Annual OSHA penalties for safety violations (2002): $149,000,000
Annual Workers Compensation Premiums (2001): $26,000,000,000
Estimated Annual Wage Premiums for Risky Activities (2004 dollars): $245,000,000,000
His point: Market incentives for worker safety dwarf legal incentives, which in turn dwarf regulatory incentives. The level of safety we see in the workplace today is about the same as the level we’d see if government just looked the other way.
Addendum: This picture shows how much OSHA has increased American job safety.