Final answer:
Abrasive blasting materials containing more than 1% free silica or significant lead content are not used due to associated health risks, with the 1% free silica figure coming from OSHA regulations.
Step-by-step explanation:
Abrasive blasting material with a specific percentage of free silica or lead is associated with health risks, and their use is regulated. While the exact percentage may vary based on regional regulations, as a point of reference, the U.S. Occupational Safety and Health Administration (OSHA) has banned abrasive blasting materials containing more than 1% free silica. Similarly, there are regulations to limit lead exposure due to its toxicity. Lead was a common component in paint and was banned for use in housing in 1978 by the U.S. government. The U.S. Food and Drug Administration has also set limits on the amount of lead that can be used in products such as ceramics and included as a part of wine bottle packaging in the form of tin-coated foil.