We all know that lead is bad for the human body, causing an array of health and growth problems (most noticeable and severely in children). Unfortunately, it was used extensively in the production of paint throughout U.S. history due to its durability and the fact that it was washable. In fact, the U.S. government frequently endorsed its application in government buildings throughout its 55-year reign.
A Simple Timeline
Lead paints were created using white lead pigments, beginning in Colonial times. Use peaked in 1922 as many homes and buildings were painted inside and out. (Interestingly, the League of Nations had banned lead paint the very same year, but the U.S. decided not to follow suit.) In 1951, the city of Baltimore banned lead pigments in interior paints in Baltimore housing -- the first such restriction in the country. In 1955, the paint industry worked with public health officials and organizations to ban the use of lead pigments in residential paints nationwide. Use of exterior lead based paints significantly declined throughout the '50s and '60s, and ended entirely by the early 1970s.
The U.S. government passed the Lead Poisoning Prevention Act in 1971. At the time, there were varying understandings of how children could be exposed to lead and what levels were considered safe; it was not until 1974 that the government realized household dust could be a viable pathway for lead exposure. In the late '70s, comprehensive epidemiological studies began to be performed on children's blood lead levels -- in 1978, the federal government banned all consumer uses of lead paint. The standard blood lead level considered safe was 60 micrograms per deciliter; it was lowered to 10 micrograms in 1991, and further to 5 micrograms in 2012.
Get The Lead Out
Fortunately, the risk of lead paint exposure can be reduced due to examinations by home inspectors. As an added bonus, home inspections usually take less than three hours; considering the amount of damage that lead paint can cause, the time and money spent preventing such exposure is invaluable. Be sure to always request lead based paint inspections if you're in the process of purchasing a new home -- you never know what the old tenants (especially if they're old themselves) may have left behind.