The major remaining cause
of lead poisoning is lead-based paint in housing, especially housing built
before 1950, when lead paint was commonly used. Most children with elevated
lead levels are poisoned in their own homes by peeling lead-based paint
and the lead dust it generates. The mere presence of lead-based paint
in a home is not a hazard, as about 40 percent of all U.S. housing contains
some leaded paint, and the vast majority of children live safely in these
homes and apartments.
Housing age is an important predictor of risk, because the lead content
of paint varied substantially over the past century. During the first
half of the twentieth century, the lead content of paint was marketed
as a measure of its quality—the more lead the better. Prior to about
1940, leaded paints typically contained high amounts of lead, ranging
from 10 percent to as much as 50 percent. Lead was added to make paint
durable, so lead paint was frequently used in high-traffic and high-moisture
areas, including kitchens and bathrooms, exterior siding and trim, window
and door trim, stairs, porches, etc. In the early 1950s, the paint industry
began reducing lead content, although many paints still contained harmful
amounts of lead. Federal regulations limited lead content in 1972 and
effectively banned lead in residential paints in 1978.
Two situations account for the vast majority of poisoning in children.
Most commonly, children are poisoned by lead dust from deteriorated paint
in poorly maintained older housing. A lesser number of cases—though
often more serious—are caused by repainting and remodeling projects
that disrupt old painted surfaces without proper safeguards to control,
contain, and clean up lead dust. In both scenarios, small amounts of lead
dust can create substantial health risks. For example, imagine the amount
of sugar in a 1-gram packet. The same amount of lead particles evenly
spread over 100 rooms, each measuring 10 feet by 10 feet, would leave
dust levels of 100 µg/ft2, an
amount of lead that is more than twice the federal standard (40 µg/ft2)
for a hazardous level of lead on floors.
Lead in soil can come from many sources, including exterior lead-based
paint that is peeling or flaking, dust or paint chips resulting from repainting
or renovation projects, deposition from emissions of vehicles that used
leaded gasoline, and demolition of buildings with lead-based paint. The
U.S. Geological Survey estimates the mean naturally occurring lead in
soil concentration to be 16 parts per million (ppm). EPA defines a soil
lead hazard as 400 parts per million (ppm) in play areas and a 1,200 ppm
average for bare soil in the rest of the yard.
Drinking water may become contaminated with lead from pipes or solder
leached out by corrosion. EPA estimates that drinking water accounts for
10 to 20 percent of human exposure to lead. Infants may be put at increased
risk from lead in drinking water when contaminated tap water is used to
make baby formula. EPA recommends that action be taken if more than 10
percent of tap water samples exceed the action level of 15 parts per billion.
Primary prevention of lead exposure, including testing for lead content
in paint, soil, and water; housing
maintenance; and remediation
of existing hazards is key to protecting children’s
health. Lead poisoning is a concrete expression of the affordable housing
crisis, more prevalent among poor
children, children of color, and those living in older housing.
Responsible property management, the need for enforceable housing quality
standards that are both practical and cost-effective, and increased resources
are needed to protect high-risk communities and preserve the nation’s
affordable housing stock.
Environmental Health Perspectives, The Prevalence of Lead-Based
Paint Hazards in U.S. Housing - www.hud.gov/offices/lead/techstudies/LeadPaintHousingSurvey.pdf
U.S. Environmental Protection Agency - www.epa.gov/lead
& www.epa.gov/safewater/lead/index.html |
