Childhood Lead Poisoning Associated with Lead Dust Contamination of Family Vehicles and Child Safety Seats --- Maine, 2008

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.

Reported by: T Bernier, S Lee, A May, MPH, E Frohmberg, A Smith, ScD, Maine Center for Disease Control and Prevention; C Kennedy, DrPH, MJ Brown, ScD, National Center for Environmental Health, JE Tongren, PhD, EIS Officer, CDC.

Editorial Note:
These are the first reported cases of lead poisoning caused by elevated lead dust associated with child safety seats. These reports highlight the need to consider expanding lead dust testing to include vehicles and child safety seats when occupational exposure is suspected, and to reinforce lead safety work practices. During 2003--2004, 95% of reported elevated BLLs in adults were related to occupational exposures, particularly in the industry subsector of painting, which had the highest numbers of lead-exposed workers (8). Persons exposed to lead at work can transport lead dust home, inadvertently posing an exposure risk to household contacts, especially children who are most susceptible to poisoning.

Take-home lead exposures are known to present health risks to children (1,2) and previous studies have made recommendations to monitor lead levels among children exposed to take-home lead and to prevent contamination of the vehicle and home (1--4,6). However, scientific data are lacking regarding lead dust contamination of vehicles and child safety seats, and no standards exist for acceptable levels of lead contamination in personal vehicles. Surface swabs and wipes are available for use as screening tools to detect the presence of lead contamination on surfaces and verify the effectiveness of cleaning and other preventive measures,†† although, their use on soft surfaces (i.e., child safety seats) has not been evaluated (9). Take-home lead exposures from the workplace can be reduced by implementing lead safety measures, including provisions for use of personal protective equipment (respirators, clothing, shoes, and gloves), correct hygiene (taking showers, washing hair, and changing clothes and shoes before going home), lead-safe work practices, and medical surveillance (10).

These incidents underscore the importance of early identification of children at risk for take-home lead poisoning. The Maine mandate for blood lead testing led to identification of these cases, and environmental investigations targeting the vehicle and child safety seats were critical in identifying and removing the exposure source. However, the children in this study might not have been tested had they not been on Medicaid, particularly because clinical signs and symptoms of lead poisoning are not seen at these venous BLLs and the occupational exposure might have gone unrecognized by the provider. Two parents had already stopped working as painters, thus had no current occupational exposure, yet lead dust remained in their vehicles and on child safety seats. Targeted blood testing for early identification of child lead poisoning and subsequent investigations to remove the source of exposure are critical (5).

The findings in this report are subject to at least two limitations. First, families were reluctant to name employers and seek assistance from state or federal occupational programs, therefore no occupational investigations were conducted. Second, neither standardized testing methods nor thresholds are available for lead dust in vehicles and child safety seats. Maine's sampling technique for dust testing in child safety seats and vehicles developed over time as information from these cases became available. MCLPPP also used the current EPA standard for lead dust inside the home, which might not be a sufficiently safe level in the closed environment of a vehicle or child safety seat.

As a result of this case series, MCLPPP has reformulated its lead risk assessment and investigation protocol to include testing of vehicles and child safety seats. To reduce the number of take-home lead cases among children, further study is required to 1) document the extent of child safety seat lead contamination, 2) develop effective vehicle and child safety seat testing methods, and 3) determine effective vehicle/child safety seat decontamination methods.

References
Whelan E, Piacitelli G, Gerwel B, et al. Elevated blood lead levels in children of construction workers. Am J Public Health 1997;87:1352--5.
Roscoe RJ, Gittleman JL, Deddens JA, Petersen MR., Halperin WE. Blood levels among children of lead-exposed workers: a meta-analysis. Am J Ind Med 1999;36:475--81.
Piacitelli G, Whelan E, Sieber K, Gerwel B. Elevated lead contamination in homes of construction workers. Am Ind Hyg Assoc J 1997;58:447--54.
Piacitelli GM, Whelan EA, Ewers LM, Sieber WK. Lead contamination in automobiles of lead-exposed bridgeworkers. Appl Occup Environ Hyg 1995;10:849--55.
CDC. Recommendations for blood lead screening of Medicaid-eligible children aged 1--5 years: an updated approach to targeting a group at high risk. MMWR 2009;58(No. RR-9).
American Academy of Pediatrics. Screening for elevated blood lead levels. Pediatrics 1998;101:1072--8.
CDC. US total blood lead surveillance report, 1997--2006. Atlanta, GA: US Department of Health and Human Services, CDC; 2009. Available at http://www.cdc.gov/nceh/lead/data/state_confirmed_byyear_1997_2006total.pdf.
CDC. Adult blood lead epidemiology and surveillance --- United States, 2005--2007. MMWR 2009;58;365--69.
Esswein EJ, Boeniger MF, Ashley K, inventors; US Department of Health and Human Services, assignee. Handwipe disclosing method for the presence of lead. United States patent US 6248593. June 19, 2001.
Virji MA, Woskie SR, Pepper LD. Skin and surface lead contamination, hygiene programs, and work practices of bridge surface preparation and painting contractors. J Occup Environ Hyg 2009;6:131--42.
* Occupational Safety and Health Administration (OSHA). Lead standard 1910.1025. Lead standard in construction 1926.62.

† Lead Poisoning Control Act. 2002 Maine Revised Statutes, Title 22. Available at http://www.mainelegislature.org/legis/statutes/22/title22sec1317-D.html. Requirement for testing of all children 1 and 2 year old on Medicaid Section 1905(r)(5) of the Social Security Act and the federal Omnibus Budget Reconciliation Act of 1989.

§ EPA. Guidance for the sampling and analysis of lead in indoor residential dust for use in the integrated exposure uptake biokinetic (IEUBK) model, December 2008, OSWER 9285.7-81.

¶ EPA. Identifying lead hazards in residences, April 2001. EPA 747-F-01-002. Available at http://www.epa.gov/lead.

** OSHA response to the question, "What procedures should workers who are exposed to lead follow at the end of the day?" Available at http://www.dol.gov/elaws/osha/lead/freqd.asp. Maine Center for Disease Control and Prevention. Don't take lead home from your job! Available at http://www.maine.gov/DHHS/eohp/lead/documents/TakeHomeLead.pdf.

†† National Institute of Occupational Safety and Health method 9105, available at http://www.cdc.gov/niosh/nmam/pdfs/9105.pdf.

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Childhood Lead Poisoning Associated with Lead Dust Contamination of Family Vehicles and Child Safety Seats --- Maine, 2008