What common component was often present in painted surfaces before 1986?

The correct answer is lead paint. Prior to 1986, lead-based paint was commonly used in homes and buildings because it provided good durability and a vibrant color finish. The harmful effects of lead exposure, particularly for young children and pregnant women, were not fully understood until later, which is why it was widely used without the precautions that are required today.

Lead paint became a significant health concern, leading to the U.S. Consumer Product Safety Commission banning its use in residential properties in 1978. Although other types of paints, like oil-based and latex, have also been used in various contexts, the specific concern surrounding lead paint is a key reason why it is notable in historical discussions about painted surfaces prior to regulatory changes in the mid-1980s.