Addressing Lead Hazards in Historic Buildings
The desire to remove lead hazards, often thought to be the result of deteriorating lead paint that leaves traces of lead dust in soil and on household surfaces, often leads to the removal of significant historic features. Recent studies have suggested that lead hazards stem from the atmosphere and soil, not from lead-based paint. Other sources suggest maintaining and cleaning surfaces containing lead paint rather than removing hazards altogether.
Below are excerpts from various scholarly and/or authoritative publications. For more information, please visit the links provided and the additional resources at the bottom of the article.
Description of Lead and its Origins
"Elemental lead is a heavy, soft, and malleable bluish metal that has been used for thousands of years. Its favorable physical and chemical properties account for its versatility and extensive use in many common products including lead acid batteries, ammunition, chemicals (e.g., plastic stabilizers, pigments, and ceramic glazes), alloys (e.g., solder in piping and electronics), pipe/sheet lead, and radiation and cable sheathing. Centuries of mining, smelting, and use have released millions of tons of lead into the environment. With no know or foreseeable technology to render anthropogenic sources of environmental lead harmless, it remains ubiquitous in air, water, soil, dust, and in older homes and commercial structures. As a result, practically all people have some exposure to lead of anthropogenic origin."
Source: Environmental Protection Agency: "Lead; Identification of Dangerous Levels of Lead; Proposed Rule." Federal Register, Vol. 63, No. 106, pp. 30301-30355, June 3, 1998. http://www.epa.gov/EPA-TOX/1998/June/Day-03/t14736.htm
Exterior Lead Hazards More Prevalent Than Interior Hazards
"Children and adults living in urban areas where surface soils are contaminated with lead may become exposed through indoor and outdoor inhalation of lead dust and ingestion of lead deposited within home and outdoor surfaces. Because resuspension of lead from contaminated soil appears to be driving seasonal child pediatric blood lead fluctuations, concomitantly, we suggest that lead-contaminated soil in and of itself may be the primary driving mechanism of child pediatric blood lead poisoning in the urban environment."
Source: Filippelli, Gabriel M., Christopher R Gonzales, David L. Johnson, Mark A.S. Laidlaw, and Howard W. Mielke, "Seasonality and Children's Blood Lead Levels: Developing a Predictive Model Using Climactic Variable and Blood Lead Data from Indianapolis, Indiana, Syracuse, New York, And New Orleans, Louisiana (USA)," Environmental Health Perspectives vol. 113, 2005. http://www.ehponline.org/members/2005/7750/7759.pdf
"Interior entry floors had significantly higher dust lead loadings than other interior floor surfaces... Further analysis suggests that entry floors serve as a pathway of leaded dust from the building exterior to the interior."
"Blood lead levels went to increase during the summer....Seasonal influences were apparent, with higher levels in the summer and lower levels in winter."
Source: Department of Housing and Urban Development, "Evaluation of the HUD Lead-Based Paint Hazard Control Grant Program," 2004.
Specific Lead Hazards and Their Locations
"Lead-based paint that is in good condition is usually not a hazard."
"Lead dust can form when lead-based paint is dry scraped, dry sanded, or heated. Dust also forms when painted surfaces bump or rub together. Lead chips and dust can get on surfaces and objects that people touch. Settled lead dust can re-enter the air when people vacuum, sweep, or walk through it."
"Lead in soil can be a hazard when children play in bare soil or when people bring soil into the house on their shoes. Contact the National Lead Information Center "Dust-lead hazards should be addressed through intensive cleaning. If household surfaces are smooth and cleanable, regular household cleaning can probably maintain acceptably low levels of lead in dust in the absence of any event (e.g., remodeling project) that reintroduces large amounts of just contaminated with lead. Soil-lead hazards should be eliminated. Currently available options include soil removal and permanently covering the soil (i.e., paving)."
"Ingestion of lead-contaminated dust and soil through normal hand-to-mouth activity appears to be the primary pathway of lead exposure to U.S. children under 6 years of age. (Refs. 3 and 4.), Dust is contaminated by lead when: lead-based paint deteriorates, lead-based paint is disturbed in the course of renovation, repair, or abatement activity; or lead is tracked into, blown into, or otherwise enters the home from soil in the yard or other external sources (e.g., workplace). Soil contaminated with lead from deterioration of exterior lead-based paint, industrial emissions, and/or deposition of lead from past use of leaded gasoline may be ingested directly or contribute to indoor levels of lead-contaminated dust when tracked into the home. Children may also be exposed to lead through the ingestion of lead-based paint chips from flaking walls, windows, and doors or from chewing on surfaces covered with lead-based paint. Other sources of lead exposure include, but are not limited to, lead-contaminated food and drinking water and occupational exposure to dust and airborne lead particles."
"Based on the HUD National Survey, EPA estimates that 13 million or 17 percent of pre-1980 privately-owned home have "elevated" lead dust levels, which were defined at the time of the Survey as lead dust exceeding 200 micrograms per square foot on floors, 500 mcg/ft^2 on window sills, or 800 mcg/ft^2 on window troughs (Ref. 8). Homes with non-intact lead-based paint were five times more likely to have elevated lead dust levels than homes with intact lead paint (Ref. 9)."
"Lead-based paint, a toxic material , was widely used in North America on both the exteriors and interiors of buildings until well into the second half of the twentieth century. If a "historic" place is broadly defined in terms of time as having attained an age of fifty years, this means that almost every historic house contains some lead-based paint. In its deteriorated form, it produces paint chips and lead-laden dust particles that are a known health hazard to both children and adults.
The premise of this Preservation Brief is that historic housing can be make lead-dafe for children without removing significant decorative features and finishes, or architectural trimwork that may contribute to the building's historic character. Historic housing--encompassing private dwellings and all types of rental units--is necessarily the focus of this Brief because federal and state laws primarily address the hazards of lead and lead-based paint in housing and day-care centers to protect the health of children under six years of age. Rarely are there mandated requirements for the removal of lead-based paint from non-residential buildings.
Typical health departments guidelines call for removing as much of the surfaces that contain lead-based paint as possible. This results in extensive loss or modification of architectural features and finished and is not appropriate for most historic properties. A great number of federally-assisted housing programs are moving away from this approach as too expensive and too dangerous to the immediate work environment. A preferred approach, consistent with The Secretary of the Interior's Standards for the treatments of Historic Properties, calls for removing, controlling, or managing the hazards rather than wholesale-or even partial-removal of the historic features and finishes. This is generally achieved through careful cleaning and treatment of deteriorating paint, friction surfaces, surfaces accessible to young children, and lead in soil. Lead-based paint that is not causing a hazard is thus permitted to remain, and, in consequence, the amount of historic finished, features and trimwork removed from a property is minimized."
Conduct regular building checks for potential problems, such as:
National Park Service: "Preservation Brief 37 Appropriate Methods for Reducing Lead Paint Hazards in Historic Housing," by Sharon Park
Environmental Protection Agency: "Lead in Paint, Dust, and Soil"
Department of Housing and Urban Development:
"Reference Library - Residential Lead Desktop Reference"
National Conference of State Legislatures Lead Statutes Database, 2006.
Filippelli, Gabriel M., Christopher R Gonzales, David L. Johnson, Mark A.S. Laidlaw, and Howard W. Mielke, "Seasonality and Children's Blood Lead Levels: Developing a Predictive Model Using Climactic Variable and Blood Lead Data from Indianapolis, Indiana, Syracuse, New York, And New Orleans, Louisiana (USA)," Environmental Health Perspectives vol. 113, 2005.
Source: Environmental Protection Agency, "Lead in Paint, Dust, and Soil: Basic Information."
http://www.epa.gov/lead/pubs/leadinfo/htm#facts
Suppressing and Preventing Lead Hazards
Source: Environmental Protection Agency: "Lead; Identification of Dangerous Levels of Lead; Proposed Rule." Federal Register, Vol. 63, No. 106, pp. 30301-30355, June 3, 1998.
http://www.epa.gov/EPA-TOX/1998/June/Day-03/t14736.htm
Source: Sharon Park, "Preservation Brief 37: Appropriate Methods for Reducing Lead Paint Hazards in Historic Housing," Technical Preservation Services, National Park Service, 1995.
http://www.cr.nps.gov/hps/tps/briefs/brief37.htm
-Flaking or peeling paint
-Water damage to paint, plaster, wood
-Plumbing or roof leaks
-Painted doors and windows that do not operate
Source: U.S. Department of Housing and Urban Development, "Lead Paint Safety: A Field Guide for Painting, Home Maintenance, and Renovation Work,"
http://www.hud.gov/offices/lead/training/LBPguide.pdf
Additional Resources
http://www.cr.nps.gov/hps/tps/briefs/brief37.htm
http://www.epa.gov/lead
"Evaluation of the HUD Lead-Based Paint Hazard Control Grant Program," May 2004
http://www.centerforhealthyhouseing.org/HUD_National_Evaluation_Final_Report.pdf
http://www.hud.gov/office/lead/leadreferencelibrary.cfm
http://www.ncsl.org/programs/envirom/envhealth/leadStatutesdb.cfm
http://www.ehponline.org/members/2005/7750/7759.pdf