Final answer:
The Poison Prevention Packaging Act (PPPA) of 1970 requires child-proof packaging for prescription and over-the-counter (OTC) drugs to prevent child ingestion of hazardous substances.
Step-by-step explanation:
The law that requires all prescription and over-the-counter (OTC) drugs to be in child-proof packaging, unless specified or requested otherwise, is known as the Poison Prevention Packaging Act (PPPA) of 1970. This act was put in place to reduce the risk of children ingesting hazardous substances, which can lead to serious injury or even death. The PPPA is enforced by the Consumer Product Safety Commission (CPSC), which determines which substances require child-resistant packaging. It applies broadly to various household substances, chemicals, and medications. There are specific criteria and regulations that manufacturers and pharmacies must adhere to in order to comply with this act.