[1][2] Its main goal is to ensure that employers provide employees with an environment free from recognized hazards, such as exposure to toxic chemicals, excessive noise levels, mechanical dangers, heat or cold stress, or unsanitary conditions.

[10] After the Civil War, some improvements were made through the establishment of state railroad and factory commissions, the adoption of new technology (such as the railway air brake), and more widespread availability of life insurance.

[12] Backed by trade unions, many states also enacted workers' compensation laws which discouraged employers from permitting unsafe workplaces.

[10] These laws, as well as the growing power of labor unions and public anger toward poor workplace safety, led to significant reductions in worker accidents for a time.

The health effects of these chemicals were poorly understood, and workers received few protections against prolonged or high levels of exposure.

Some labor leaders seized on the public's growing unease over chemicals in the environment, arguing that the effect of these compounds on worker health was even worse than the low-level exposure plants and animals received in the wild.

[15] Led by the United States Chamber of Commerce and the National Association of Manufacturers, the legislation was widely opposed by business.

[15] However, Representative James G. O'Hara and Senator Harrison A. Williams introduced a much stricter bill similar to the Johnson legislation of the year before.

[13] The compromise bill established the independent research and standard-setting board favored by Nixon, while creating a new enforcement agency.

Union leaders pressured members of the conference committee to place the standard-setting function in the Department of Labor rather than an independent board.

[20] Unions also agreed to removal of a provision in the legislation which would have let the Secretary of Labor shut down plants or stop manufacturing procedures which put workers in "imminent danger" of harm.

[20] In exchange for a Republican proposal to establish an independent occupational health and safety research agency, Democrats won inclusion of the "general duty" clause and the right for union representatives to accompany a federal inspector during inspections.

The Act applies to employers as diverse as manufacturers, construction companies, law firms, hospitals, charities, labor unions and private schools.

Section 8 permits OSHA inspectors to enter, inspect and investigate, during regular working hours, any workplace covered by the Act.

Detailed technical bulletins called material safety data sheets (MSDSs) must be posted and available for employees to read and use to avoid chemical hazards.