When lead-based paint was marketed before 1978, it was a legal product in great demand because it was washable and durable. It was repeatedly endorsed by the U.S., state, and local governments and specified for use on government buildings until the mid-1970s. Its use peaked in 1922, and by 1940 the use of white lead pigments for interiors was on the way out.
When white lead pigments were used in paints, currently reported risks to children were unknown and unknowable. That’s because medical knowledge of the risks of lead evolved over a century. As plaintiffs’ experts admitted in the Santa Clara, California trial, information on the risks of lead paint was always publicly available and known to public health officials of the day, and the lead pigment and paint manufacturers never conducted secret studies or hid information from the public or public health officials.
What follows is a brief chronological history of the use of lead-based paint in the United States:
- Use of white lead began in the Colonial times and ultimately peaked in 1922.
- In 1951, Baltimore banned the use of lead pigment in interior paint in Baltimore housing – the first such restriction in the country.
- In 1955, the industry, working with public health officials and organizations, adopted a voluntary national standard to prohibit, in effect, the use of lead pigments in interior residential paints.
- Through the 1950s and 1960s, the use of exterior lead-based paint declined significantly, and ended by the early 1970s.
- In 1971, the federal Lead Poisoning Prevention Act was passed.
- In 1978, the federal government banned consumer uses of lead paint.
As uses of lead pigments in paints evolved, so did the primary pathways through which children were thought to be exposed to lead and the level of exposure thought to be safe. It was not until 1974 that household dust emerged as a possible pathway for lead exposure. Only in the late 1970s did comprehensive epidemiological studies of children’s blood lead levels begin, raising modern concerns about low asymptomatic blood lead levels. When the Lead Poisoning Prevention Act was passed in 1971, a blood lead level of 60 micrograms per deciliter was considered safe. In 1991, acknowledging the change was based on “very recent research,” the CDC lowered the blood lead level of concern to 10 or above, where it remained until 2012, when the CDC established a new measure of blood lead levels – the “reference” level – that was set to include the highest 2.5 percent of tested children. That reference value, which is not health-based and will change over time, is currently five micrograms per deciliter.
The evolving knowledge of risk was acknowledged by Dr. Jane Lin-Fu, a former Department of Health, Education and Welfare (HEW) public health official, who was HEW’s leading expert on lead risks to children in the 1960s and 1970s. She wrote in 1985, long before there had been any lead pigment trials:
“[I]t should be obvious that what constitutes the health effects of lead is an evolving concept that has changed dramatically since lead toxicity was first recognized in ancient times.”
“In the last 10 to 15 years [since 1970-1985], as scientific advances and modern technology have provided more sensitive measures of biochemical, psychological, and electro physiological changes associated with relatively low levels of lead exposure, the concept has undergone further scrutiny and changes that were fraught with controversies.”
For more information on the history of lead-based paint, click here (PDF).