Which of the following substances is commonly regulated by OSHA?

The correct answer focuses on toxic substances in the workplace because OSHA, the Occupational Safety and Health Administration, is primarily responsible for ensuring safe and healthy working conditions for employees. This includes the regulation of hazardous materials that could pose a risk to workers' health and safety. Toxic substances can include chemicals, solvents, and other materials that, if not properly managed, could lead to illnesses, injuries, or even fatalities on the job.

While cosmetic products, household cleaners, and food packaging materials may have safety guidelines or regulations, they are not specifically regulated by OSHA in the workplace context. Instead, these items might fall under the jurisdiction of other agencies, such as the FDA for cosmetics and food products or the EPA for certain cleaning agents. Thus, because OSHA's mandate is to protect workers from workplace hazards, the emphasis on toxic substances directly aligns with their regulatory focus.