Lead-In-Paint Information
Contents
1. History of Lead-Based Paint
2. Hazard of Lead
3. Regulations and Definitions
4. Do I have lead-based paint in my house?
History of Lead-Based Paint
Lead oxide is a white pigment used since ancient times; it was used rather than any of the many other white mineral pigments because of its greater hiding power. Prior to 1940, lead was in almost every paint. As titanium dioxide, a white pigment of hiding power superior to lead oxide, became economic, the use of lead oxide diminished. By 1978, when regulations limited the allowable lead in paint were implemented, the use of lead oxide had all but stopped already.
Lead chromate pigments in colors of yellow, orange or green (when mixed with a blue pigment) were also quite prevalent during the same period of use as lead oxide. Lead chromate paint is still used for safety paints, such as the paint on traffic lines or fire hydrants.
Lead was burned in leaded gasoline from the 1930’s to 1970’s, and much of this lead still lies in the soil adjacent to major roads.
Hazard of Lead
Lead is a poisonous heavy metal which may cause the following symptoms: anemia, enzymatic changes, abdominal cramping, palsy or shaking, depressed IQ and attention disorders. It can be absorbed into the body through breathing fumes or particles, eating or drinking contaminated food, or through the skin (for organic lead compounds, such as leaded gasoline).
The major hazards to the general public today are existing lead-based paint, and soil contaminated by a combination of deteriorating paint and auto fumes. Children, with their still developing neurological systems and poorer hygienic practices, are at greater risk than are adults. It is thought that an important pathway of lead into a child is by hand, as the child crawls along a contaminated floor, then puts its hand into its mouth.
Regulations and Definitions
Lead is regulated in air, paint, dust, blood, water and waste.
Air: OSHA – permissible exposure limit (for 8 hr average)= 50 ug/m3
Paint in place: HUD – >1 mg/cm2 or >0.5% = positive
New Manufactured Paint: CPSC – maximum allowable = 600 ppm (0.06%)
Dust (after abatement): maximum on floors = 40 ug/ft2; on window sills = 250 ug/ft2; in window troughs = 400 ug/ft2
Blood: CDC – action level for children = 10 ug/100ml; OSHA – maximum allowable level for workers = 40 ug/100ml
Water: EPA – maximum allowable = 15 ug/L
Waste: EPA – hazardous waste is >5 ppm in a TCLP test
Do I have lead-based paint in my house?
Generally, the older a house is, the greater the chance of lead-based paint, although any house built prior to 1978 is considered to possibly contain it. A house built prior to 1940 is almost guaranteed to have lead-based paint somewhere in it.
Lead paint does not look significantly different from non-lead paint to be identified. Lead-contaminated dust or dirt does not appear different than any other. Analytical testing is the only way to tell where the lead is.
Testing can be done on site or in the laboratory.
On-site testing is commonly performed using a portable x-ray fluorescence spectrometer (XRF). The instruments are designed to determine whether a paint film is above or below the HUD limit of 1 mg/cm2. In other words, it will tell you whether you should think about abating paint that children live around. The strengths of the portable XRF are that 1) the lead readings are immediate, and previous readings can be used as a guide to take additional readings, and 2) the readings are done relatively fast (and cheaply). The weaknesses of the portable XRF are that 1) readings can be misleading if not correctly interpreted, and 2) the instruments usually do not have the sensitivity to detect lead down to the CPSC level allowable in new paint.
Laboratory testing is performed by a number of analytical techniques, commonly atomic absorption (AA) or inductively coupled plasma (ICP). Lab tests require a physical sample (paint chips) to be taken, which are destroyed during testing. Generally, the lab tests are more sensitive and more precise than the portable XRF, and are easily able to detect lead far below the CPSC level of 600 ppm. The disadvantages of lab tests are that they are more expensive, test for test, than XRF tests, and they are destructive.
