Job safety and health is legally ensured by the Occupational Health and Safety Act, and came about as a result of millions of Americans being injured yearly on the job and the discovery of how dangerous chemicals in the workplace affected worker's health. Insurance and liability have led to increasingly safer job conditions, and sparked major changes in the work environment, including the mass removal of asbestos from all work areas. Most employers take the extra precaution of offering or even mandating that employees complete basic health and safety classes so that they are educated on first aid and what to do in an emergency situation. Some job sites require more complex training and certification. It is up to employers to make sure all employees are up-to-date and properly trained when performing ﾑdangerous' jobs that may require a special skill set. It is also up to employers to provide safe work environments.