Lead paint

Lead paint or lead-based paint (LBP) is paint containing lead, a heavy metal, that was used as pigment, with lead(II) chromate (PbCrO₄, "chrome yellow") and lead(II) carbonate(PbCO₃, "white lead") being the most common. Lead was also added to paint to speed drying, increase durability, retain a fresh appearance, and resist moisture that causes corrosion. However it is one of the major health and environmental issues with paint. In some countries lead continues to be added to paint intended for domestic use whereas in others regulation exists that prohibits this, though lead paint may still be found in older properties painted prior to the introduction of such regulation e.g. in the U.S. and the U.K. and Australia. Although lead has been banned in household paint since 1978, traffic paint still may contain lead. Alternatives such as water-based, lead-free traffic paint are readily available. Many states and federal agencies have changed their purchasing contracts to specify lead-free traffic marking paint.

Toxicity

Main article: Lead poisoning

Although lead improves paint performance, it is a dangerous substance. It is especially damaging to children under age six whose bodies are still developing. Lead causes nervous system damage, stunted growth, and delayed development. It can cause kidney damage and affects every organ system of the body. It also is dangerous to adults, and can cause reproductive problems for both men and women. Lead paint is particularly dangerous because it tastes sweet therefore encouraging children to put lead chips and toys with lead dust in their mouths.

One myth related to lead-based paint is that children must eat leaded paint chips to develop lead poisoning. In fact, childhood lead exposure can occur by way of ingestion of lead dust through normal hand-to-mouth contact during which children swallow lead dust dislodged from deteriorated paint or leaded dust generated during remodelling or painting

Regulation

The European Union has passed a directive controlling lead paint use.

The United States government's Consumer Product Safety Commission banned lead paint in 1977 (16 Code of Federal Regulations CFR 1303). In an announcement dated September 2, 1977, "The U.S. Consumer Product Safety Commission (CPSC) has culminated a major regulatory proceeding by issuing a final ban on lead-containing paint and on toys and furniture coated with such paint. This action was taken to reduce the risk of lead poisoning in children who may ingest paint chips or peelings.".

Effective April 22, 2010, the US EPA now requires that all renovators who work in homes built pre 1978 and disturb more than six square-feet of lead paint be RRP certified. The new regulation will affect over 100,000 renovators across the country. Renovators can find out more about the program and training locations at.

For manufacturers, the CPSC instituted the Consumer Product Safety Improvement Act of 2008 which changed the regulations on lead content of paint from 0.06% (w/w) to 0.009%, or 90ppm, on August 14, 2009.

Lead paint in art

In art, lead white is known as flake white, also sometimes known as Cremnitz white. Flake white is traditionally considered to be the most structurally sound underpainting layer for oil painting, possessing a combination of flexibility, toughness, and permanence not found in other paints, and certainly not in the other white pigments. Genuine flake white is difficult for artists to obtain in many countries, even though other toxic paints (such as the cadmium-based colors) may be readily available. Where flake white is currently available to artists, it is usually only in small tubes designed for painting, not in the larger cans traditionally used for underpainting (coating the canvas prior to the actual painting) which for centuries was flake white's most important purpose.

Artists' use of lead paint is mostly associated with oil painting on linen or cotton canvas. In the relatively rare cases where it has been used in works on paper, it will often become discolored over long periods of time. This is due to the reaction of the lead carbonate in the paint with traces of hydrogen sulfide in the air and with acids, often from fingerprints. As a result, many older works on paper that used lead paint now show some discoloration.

Substitutes

Paint manufacturers replaced white lead with a less toxic substitute, titanium white (based on the pigment titanium dioxide) which was first used in paints in the 19th century. (In fact, titanium dioxide is considered safe enough to use as a food coloring and in toothpaste, and is a common ingredient in sunscreen.) The titanium white used in most paints today is often coated with silicon or aluminum oxides for better durability. Titanium white has been criticized for leading to "chalkiness" when mixed with colors, and the possibility of decreased permanence of organic pigments mixed with it due to its high refractive index.

Zinc white is less opaque than titanium white, and is often seen as a superior white for lightening other pigments in mixtures. Although zinc white is the standard white for the watercolor medium it has long been of debatable permanence in oils. Critics of the pigment argue that its use leads to excessive cracking and delamination, even when very sparingly mixed with other pigments such as lead white.

Some art-supply manufacturers supply a "lead white hue," a mixture, usually of titanium and zinc white, which attempts to imitate the hue of genuine lead paint without the toxicity. It does not, however, have the desirable structural (physical) properties of lead white.

Real estate maintenance and renovation

Humans can be poisoned during unsafe renovations or repainting jobs on housing that has lead paint. Therefore, it is encouraged to carefully stabilize any deteriorated (peeling, chipping, cracking, etc.) paint in a lead-safe manner and take precautions during preparation for repainting.

Lead-based paint on the exterior of structures weathers to give flakes and powder. The degraded paint particles accumulate in the soil near the structure. Lead-based paint used on interior surfaces can also degrade to produce lead-containing dust. Sanding coatings prior to repainting generates lead dust. Sanding the exterior of a structure without proper equipment can cause lead contamination inside the structure. Methods used to remove lead paint can themselves generate lead dust. This is particularly true when unacceptable methods and work practices are used. Poorly performed abatement can be worse than no abatement. Micron-sized lead dust particles can remain airborne for substantial periods and cannot be completely removed by standard cleaning methods. When working on old painted surfaces, assume that one or more of the paint coats contain lead. Take precautions accordingly.

See also

• Lead-based paint in the United States
• Lead-based paint in the United Kingdom
• Environmental issues with paint

Further reading

• Rutherford J. Gettens; Hermann Kühn; W. T. Chase (1967). "Identification of the Materials of Paintings: Lead White". Studies in Conservation 12 (4): 125–139.. JSTOR 1505410. 
• Suing the Tobacco and Lead Pigment Industries: Government Litigation as Public Health Prescription by Donald G. Gifford. Ann Arbor, University of Michigan Press, 2010. ISBN 978-0-472-11714-7

External links

• Case Studies in Environmental Medicine (CSEM): Lead Toxicity
• Lead in Paint, Dust, and Soil
• National Pollutant Inventory (Australia) - Lead and Lead Compounds Fact Sheet
• Manufacture of White Lead Pigment
• Lead Paint Safety: EPA's Field Guide for Painting, Home Maintenance, and Renovation Work
• National Survey of Lead and Allergens in Housing
• How to find a certified EPA Lead Paint Contractor
• An Annotated Bibliography of Works concerning Paint and Colour prepared by Patrick Baty. Many early sources on lead paint are listed and discussed.
• Some Myths concerning Lead Paint