Childhood Lead Poisoning Associated with Lead Dust Contamination of Family Vehicles and Child Safety Seats – Maine, 2008
Persons employed in high-risk lead-related occupations can transport lead dust home from a worksite through clothing, shoes, tools, or vehicles (1-4). During 2008, the Maine Childhood Lead Poisoning Prevention Program (MCLPPP) identified 55 new cases of elevated (≥15 µg/dL) venous blood lead levels (BLLs) among children aged <6 years through mandated routine screening (5,6). Although 90% of childhood lead poisoning cases in Maine during 2003–2007 had been linked to lead hazards in the child's home, no lead-based paint or dust or water with elevated lead levels were found inside the homes associated with six of the 2008 cases (i.e., five families, including one family with two affected siblings). An expanded environmental investigation determined that these six children were exposed to lead dust in the family vehicles and in child safety seats. The sources of the lead dust were likely household contacts who worked in high-risk lead exposure occupations. Current recommendations for identifying and reducing risk from take-home lead poisoning include 1) ensuring that children with elevated BLLs are identified through targeted blood lead testing, 2) directing prevention activities to at-risk workers and employers, and 3) improving employer safety protocols. State and federal prevention programs also should consider, when appropriate, expanded environmental lead dust testing to include vehicles and child safety seats.
Lead poisoning has decreased among children in the United States because of federal, state, and community efforts to reduce exposure (7). Federal bans on leaded gasoline and lead-based paint, and improvements in occupational safety and health standards* have helped mitigate exposure to lead, especially among children. MCLPPP responds to all reported elevated blood lead levels ≥10 µg/dL. Children with venous BLLs ≥15µg/dL automatically trigger an environmental investigation to determine the lead sources, and children are monitored until their venous BLLs are <10µg/dL.
For this study, a case of lead poisoning was defined by a confirmed venous BLL ≥15 µg/dL in a child aged <6 years living in Maine. All cases were identified through mandated blood lead testing for children at ages 1 year and 2 years following CDC targeted lead testing recommendations (5,6).† A case of take-home lead poisoning was defined by 1) a confirmed venous BLL ≥15 µg/dL among children aged <6 years living in Maine, 2) a household contact in a high-risk lead-related occupation, and 3) environmental lead dust sampling of vehicle and child safety seat ≥40 µg/ft2, with no detectable lead-based paint hazards present in the home.
When these investigations began, MCLPPP contacted each child's family and offered general lead education, nursing case management, and environmental lead investigations by licensed lead risk assessors to determine the likely sources of the poisoning. Families were interviewed using a MCLPPP risk-assessment questionnaire to determine other possible exposures. Radiograph fluorescence analysis was used to determine whether lead-based paint was in the homes. Lead dust wipe samples were taken using the Environmental Protection Agency (EPA) standard lead dust loading methodology in the homes.§ For the cases described in this report, MCLPPP also directed investigators to perform additional dust sampling in the family vehicles and child safety seats because household members had occupations at high risk for lead exposure. The EPA acceptable lead dust standard is <40 µg/ft2 for floors inside the home, but no lead standards have been set for vehicles or child safety seats.
The six children with take-home lead poisoning, including two siblings in one family, ranged in age from 4 to 28 months, and had a median venous BLL of 21 µg/dL (range: 15–32 µg/dL). Among the five families, contacts included four persons who currently or recently worked in painting and paint removal, and one who was a self-employed metals recycler. The workers reported no lead-related occupational safety measures provided by their employers at work sites.
Four of the five homes were built after 1978, the year lead-based paint was banned. No lead-based paint was detected by radiograph fluorescence analysis inside the five homes. In two of five homes, lead dust was detected in exterior areas where family members removed and kept work clothes, including an entryway/deck (110 µg/ft2), another entryway (1,200 µg/ft2), and a laundry room (40 µg/ft2). Five family vehicles (one family did not own a vehicle and one family had two) tested positive for lead dust with a median of 550 µg/ft2 for driver/passenger seats (range: 49–2,100 µg/ft2) and a median of 1,570 µg/ft2 for driver/passenger floors (range: 240–2,900 µg/ft2). All child safety seats (n = 6) tested positive for lead dust with a median of 98 µg/ft2 (range: 43–420 µg/ft2). Three safety seats were stored in the vehicle (median lead dust: 120 µg/ft2 [range: 43–420 µg/ft2]); the other three were removed and kept in the home when not in use (median lead dust: 95 µg/ft2 [range: 50–100 µg/ft2]).
MCLPPP determined that the primary source of lead exposure was lead dust in the family vehicles and on the child safety seats (Table), and provided recommendations to prevent continued exposure. Persons who are exposed to lead at work or through hobbies are advised upon finishing the workday to 1) place lead-contaminated clothes, including shoes and personal protective equipment, in a closed container for laundering or cleaning; 2) take a shower and wash hands, face, and hair when exposed above the permissible exposure limits; 3) change into street clothes; and 4) wash work clothes separately from all other clothes.** However, parents and household contacts reported a lack of facilities available for washing, showering, and changing clothes before entering their personal vehicles. MCLPPP also recommended thorough vacuuming and wet cleaning of the vehicle interiors and replacement of any child safety seat that tested positive for lead dust. Families were referred to the Maine Injury Prevention Program for replacement safety seats, if needed.