Lead-tainted crayons from China part I: secondary prevention in Arizona.

Editor's Note: This is part one of a two-part article on lead-tainted crayons from China. Each part highlights excellent interagency cooperation to prevent childhood lead poisoning. Part one discusses secondary prevention measures taken in Arizona, while part two focuses on primary prevention measures taken in Oregon. Part two will appear in the April 1996 issue of the Journal.

Introduction

Lead is a metal commonly found in childhood environments. Sources of lead include paint, soil, water, dust, and food. Lead is particularly damaging to the developing nervous systems and brains of young children and fetuses (1). Severe exposure to lead resulting in high blood lead levels of [greater than or equal to] 80 micrograms per deciliter ([[micro]gram]/dL) can cause coma, convulsions, and death. Minor exposure, as measured by blood lead levels as low as 10 [[micro]gram]/dL, may not cause distinctive symptoms, but is associated with decreased intelligence and neurobehavioral problems (1). In 1991, the U.S. Centers for Disease Control and Prevention (CDC) lowered the defined intervention level from 25 [[micro]gram]/dL to 10 [[micro]gram]/dL (1). The CDC states that the persistence of lead poisoning in the U.S. presents a challenge to our society, public health authorities, clinicians, and regulatory agencies (1).

CDC Guidance

Public health agencies must coordinate their activities to ensure that all aspects of childhood lead poisoning prevention - health, housing and environment - are being addressed, and to provide the most comprehensive and cost-effective services to at-risk children, their parents, and their health-care providers (1). The CDC puts forth a model that further describes the public health agencies' roles as: 1) ensuring screening services are provided to identify lead-poisoned children and define community-wide interventions, 2) analyzing surveillance and other data to identify the sources of lead in the community, exposure patterns, and high-risk populations, 3) developing and implementing a primary prevention plan that focuses on the highest-risk sources and populations to identify and remove sources of lead exposure before children are harmed, 4) ensuring medical and environmental follow-up services for poisoned children, and 5) coordinating prevention activities with other pertinent health, housing, and environmental agencies (1). The application of this comprehensive and multifaceted approach resulted in the identification of a previously unreported source of lead poisoning: lead-containing crayons imported from China. The Arizona Department of Health Services (ADHS), Office of Environmental Health, identified the lead-tainted crayons as a source of exposure during an investigation of a reported elevated blood lead level for an 11 month-old Hispanic male in Phoenix, Arizona. The following description of events and agency roles leading to the identification and eventual recall of crayons by the U.S. Consumer Product Safety Commission (CPSC) are described below in relation to the five elements of the CDC model.

The Arizona Lead Poisoning Prevention Program

In Arizona, virtually all of the blood lead screening of children occurs through the state program for the medically indigent, the Arizona Health Care Cost Containment System (AHCCCS). The AHCCCS blood lead screening program is a part of the Early Periodic Screening, Diagnosis, and Treatment program (EPSDT) and calls for the testing of all one and two year-old children as a part of the well-child check-up. Further, the protocol requires that the families of children ages six months to 72 months, presenting for the well-child check-up, are given a verbal questionnaire to determine if the children are high-risk and require earlier or more frequent blood lead screening.

TABLE 1

Environmental Sampling Results Positive for Lead.

Apartment - Orange crayon                        800 mg/kg
Grandmother's House Paint, front porch post     1100 mg/kg
Grandmother's House - Soil, front yard           110 mg/kg

The ADHS has a lead poisoning registry based on passive surveillance. Arizona law requires reporting of elevated blood lead levels [greater than or equal to] 10 [[micro]gram]/dL by physicians and laboratories to the ADHS. The purpose of laboratory reporting is to ensure complete reporting. The ADHS uses laboratory reports of elevated blood lead levels to assess the level of physician compliance with mandatory reporting. Information from laboratory reports allows staff to request reports that have not been submitted by physicians.

Once ADHS receives physician reports of elevated blood lead levels, staff contact the patient or the patient's parents to help identify lead sources and to educate about prevention. For childhood cases with levels of 10 [[micro]gram]/dL through [less than]20 [[micro]gram]/dL, ADHS staff attempt to contact the patient or family by phone and send educational materials by mail. For childhood cases of [greater than or equal to]20 [[micro]gram]/dL, ADHS staff perform an environmental investigation of the home and a detailed interview to determine lead sources, provide educational materials, and recommend appropriate interventions.

The number of reported childhood lead poisoning cases in Arizona has increased dramatically in recent years due largely to increased screening as a part of the AHCCCS program and the lowering of the defined intervention level to 10 [[micro]gram]/dL by the CDC. In 1993, 441 reported childhood lead poisoning cases were received by this office, about a 700% increase over 1992. Four hundred and eighty cases were reported in 1994 [ILLUSTRATION FOR GRAPH 1 OMITTED].

The focus of the ADHS Lead Poisoning Prevention Program is secondary prevention - using limited resources to target identified cases with environmental investigations and education. Surveillance data allow staff to begin to characterize the nature and extent of lead poisoning in the state. Information on case-demographics (age, sex, race/ethnicity, and address specifiers) and investigated sources assist in identifying high-risk populations, locations, and risk factors.

Case Study

Identification of the Lead Poisoning Case

Routine screening through the AHCCCS EPSDT program identified an 11 month-old Hispanic male in Phoenix with a blood lead level of 48 [[micro]gram]/dL on December 30, 1993. The subject case was reported to the ADHS Lead Poisoning Registry by the physician on January 4, 1994. This notification initiated subsequent follow-up activities, including identification of potential sources of lead in the child's home and development of strategies for prevention.

Environmental and Medical Follow-up

On January 7, 1994, ADHS staff conducted an investigation of the subject child's home and counseled his mother about lead poisoning prevention. Staff also investigated the maternal grandmother's home where the family lived three months previously and continued to visit, including a visit five days prior to the blood lead test. Of specific interest were the following potential sources of lead exposure: paint; paint dust; soil; folk remedies; ceramic, china, or crystal food and beverage utensils; worker take-home exposures; hobbies; imported canned food; water; nearby lead industry; nearby freeway or highway; imported or old toys; and possible exposures at previous addresses or other places where the child currently spends much time. The mother reported that the child exhibited frequent hand-to-mouth behavior. She had seen him put paint, dirt, and other objects in his mouth. The mother stated that the children were given three crayon kits of the same brand for Christmas, five days prior to the blood lead test. She reported that she had seen the child chew on at least four or five crayons, and that he had eaten at least one entire crayon. After getting a negative result with a field test kit, ADHS staff took one orange crayon for laboratory analysis. In addition, staff used home test kits on items and surfaces throughout the two homes, and selected suspicious matrices for laboratory analysis. Paint, soil, and drinking water samples were taken from both homes.

The ADHS laboratory analyzed crayon, paint, soil (2) and water (3) samples using established U.S. Environmental Protection Agency (EPA) methods. Three sources of lead were identified: crayons, exterior porch paint, and soil at the grandmother's house (Table 1). The lead content of the exterior porch paint was 1,100 milligrams per kilogram (mg/kg), below the Arizona standard of 5,000 mg/kg for lead-based paint (4). Soil lead content was 110 mg/kg, also below the 1994 Arizona Health Based Guidance Level of 500 mg/kg.

The third potential source of lead was crayons. The sampled orange crayon contained 800 mg/kg lead. The crayons were large, each weighing approximately 14 grams. There were 12 crayons per package in a molded plastic tray/carrying case with a plastic handle. The package label had been lost. The crayon wrappers were marked "CRAYONS," "NONTOXIC," and "Made in China," with two black stripes, one thick and one thin at both ends. Upon receiving the laboratory results, ADHS staff removed the remaining crayons (pieces comprising approximately nine crayons) from the home. Some of these crayons had tooth marks on them.

Medical case management was the purview of the primary physician. The child was chelated with succimer. ADHS staff provided the mother with verbal and written information about lead poisoning health effects, sources, and prevention. ADHS staff also advised her to return to her physician for repeat blood lead tests for the child, and initial blood lead tests for other family members.

Preliminary Risk Assessment

A preliminary risk assessment determined that ingestion of the crayons could result in lead poisoning of the magnitude seen in this case. It was possible that the subject child could have eaten one entire orange crayon, based on the mother's description of his behavior. Therefore, we assumed that a worse case scenario would involve the ingestion of one whole orange crayon. At 800 mg/kg, a 14 gram crayon would contain 11,200 [[micro]gram] lead. Because subacute exposure to lead in this matrix has not been studied, we approximated potential chronic and acute absorption using two different techniques.

Chronic exposure was estimated using a dietary lead exposure model. While the bioavailability of lead in wax crayons was not known, it was assumed to be much lower than the bioavailability of lead in food and water. Ryu et al. estimated a 0.24 [[micro]gram]/dL blood lead rise per microgram of dietary lead ingested daily by infants and toddlers (5). Chronically, a level of 48 [[micro]gram]/dL, as in this case, could be accounted for by the ingestion of 200 [[micro]gram] of dietary lead daily. This is substantially less than the 2,240 [[micro]gram]/day estimated to have been ingested in this case during the five-day period that the child possessed the crayons before the blood lead test. This finding is in keeping with the expectation of a low bioavailability of lead in wax leading to lower absorption of lead by the body, and illustrates the feasibility of lead poisoning on the basis of repeated crayon chewing.

The effect of acute dose on the level of lead in the blood is more difficult to predict because distribution kinetics follow a multi-compartment model dependent on time, route of exposure, and plasma-erythrocyte interactions (6,7,8). As a rough approximation, we assumed 50 percent bioavailability of lead (9) in wax and one liter per kilogram initial volume of distribution in a 10 kilogram child. Using these estimates, the acute ingestion of 11,200 [[micro]gram] would result in a blood lead level of 56 [[micro]gram]/dL. While both chronic and acute assessments were designed to be overestimates, the results persuasively indicated that ingestion of even one orange crayon posed a significant exposure.

At this time, ADHS staff knew nothing about the lead content of other crayons in the child's kit, nor about the potential for other crayon brands to contain lead. We suspected that lead was in the orange crayon for either of two reasons: 1) as a pigment or 2) as an accidental contaminant during the crayon-making process. Lead has traditionally been added to paints and other materials for color and brightness, and the bright orange shade of the crayon was similar to the color of some lead oxides and salts (10). As an accidental contaminant, possibly from the machinery used to manufacture the crayons, or some as yet unknown accidental contamination of crayon ingredients, crayons might contain lead in random and various quantities. Both of these explanations suggested the possibility that many crayons of this brand could contain lead and would pose a public health risk. ADHS staff sent health alerts and notifications to other agencies based on the preliminary "worst case scenario" risk assessments.

Primary Prevention

While the focus of the ADHS Childhood Lead Poisoning Prevention Program is secondary prevention, staff initiated primary prevention activities to educate the public about the crayon hazard and to prevent future lead poisoning.

ADHS staff sent health alerts to the county health departments in Arizona, other state and local health departments, and the media. The alerts described the lead-containing crayons, and advised parents to prevent children from eating crayons. The alerts raised international interest, resulting in hundreds of inquiries from public health officials and the public. The Oregon Health Division (OHD) responded to the news by analyzing a second brand of imported crayons from China, and found quantities of lead in a yellowish-tan crayon (830 ppm) comparable to ADHS' findings and lesser amounts of lead (up to 220 ppm) in several other colors. OHD's crayon sampling and primary prevention activities are discussed in part two of this paper (which will appear in the April 1996 issue of the Journal).

Interagency Coordination 

The identification of the lead-containing crayons, public education, and the ultimate CPSC recall of certain brands of imported crayons from China are examples of the information sharing, networking, and coordinated action required to reduce the extent of childhood lead poisoning (as also discussed in part two).

Information sharing among agencies was key to identifying the crayons as a lead source and preventing future lead poisonings. Prior to receiving the subject elevated blood lead level report, ADHS staff became aware of a U.S. Customs and CPSC report of lead-containing chalk and crayons. U.S. Customs had assisted CPSC and made 18 seizures at three U.S. ports of children's crayons and chalk, most of which contained lead (11). This report alerted ADHS staff to include searching for suspicious crayons as potential sources of lead during lead poisoning investigations.

Notification of regulatory authorities was necessary to determine the brand of the suspect crayons, and to characterize the potential public health implications based on the availability of the crayons and the potential for other crayons to contain lead. ADHS contacted the local office of the CPSC because it administers the Federal Hazardous Substances Act (FHSA), which prohibits lead in consumer products in quantities hazardous to children (12). CPSC initiated an in-depth investigation to identify the brand and source of the suspect crayons. With the assistance of the ADHS and Arizona county health departments, specifically the Coconino County Health Department, the CPSC identified an importer with crayons that appeared to be identical to the ones involved in the lead poisoning case. The CPSC found high levels of lead, comparable to the ADHS findings, in only the orange and yellow crayons.

CPSC Risk Assessment and Recall

The CPSC conducted a hazard assessment for the lead in the brand of crayons implicated in the lead poisoning case (13). The hazard assessment was based on the amount of extractable lead found. It also was based on the assumption that an "average child" will ingest 14 grams of total crayon per month, consumed randomly from all 12 crayons in the packet. The micrograms of available lead per gram of crayon was defined as the sum of the levels of extractable lead, multiplied by the dilution factor of 50. In estimating exposure the CPSC assumed: if a child consumed randomly from as many as 12 crayons in the packet, comprised of 1 crayon with significant lead content and 11 other crayons with negligible lead content, then the amount of lead exposure would be the amount of available lead in a 14 gram crayon divided by 12. This number was then converted from a monthly to an estimated daily intake by dividing by 30 days. The daily intake was additive when more than one crayon in a set contained lead. The CPSC also considered a worst case scenario based on the identified lead poisoning case in which a child would eat only the leaded crayon, where the available lead in a crayon would not be divided by 12. The CPSC concluded that the implicated brand of crayons contained enough lead to cause an "average child's" daily intake to exceed the CPSC 15 [[micro]gram]/day lead intake guideline.

On March 22, 1994, the CPSC issued a recall of the brand of crayons implicated in the Arizona lead poisoning case (14). The crayons were banned as a hazardous substance under the FHSA. The CPSC tests found that the yellow and orange crayons contained enough lead to present a lead poisoning hazard to young children who might eat or chew crayons. In addition, the crayons were mislabeled art materials under the Labeling of Hazardous Art Materials Act amendments to the FHSA (15). This law requires all art materials to be reviewed by a toxicologist for chronic hazards and to be labeled appropriately. After OHD reported high lead content in a second brand of crayons from China, CPSC expanded the investigation, resulting in a recall of a total of 13 models/kits of crayons. Part two of this paper discusses these efforts in more detail.

Conclusion

An integrated approach of screening, surveillance, prevention activities, services to the lead poisoned child, and interagency coordination were crucial to the recognition and recall of hazardous crayons. In particular, background screening and surveillance were key to the identification of this previously unknown lead poisoning risk, lead-tainted crayons. The actions initiated by the screening process benefited this child and prevented future lead exposure to children in Arizona. In addition, coordination among ADHS, the Oregon Health Division (OHD) and the CPSC reduced future lead exposure across the United States and possibly worldwide through the eventual recall of lead-tainted crayons imported from China. These public health activities are essential to the continued identification of unknown risk factors and the elimination of the persistent lead poisoning problem. The activities that culminated in the recall of lead-containing crayons are an example of public health programs that function effectively to protect human health.

REFERENCES

1. Centers for Disease Control and Prevention (1991), Preventing Lead Poisoning in Young Children, U.S. Dept. of Health and Human Services, Public Health Service, Atlanta, Ga., pp. 1,7,9,35-36.

2. U.S. Environmental Protection Agency, Office of Solid Waste (1986), Solid Waste Standard Methods (SW#846), Digestion Method Protocol #3050; Quantification for Lead by Inductively Coupled Plasma Method Protocol #6010.

3. U.S. Environmental Protection Agency, Environmental Monitoring and Support Laboratory (1979), Methods for Chemical Analyses of Water and Waste (EPA-600/4-79-020, revised March 1983), Total Recoverable Lead, Graphite Furnace Method #239.2.

4. Arizona Revised Statutes, [section] 36-1611 (1975).

5. Ryu, J.E., S.J. Fomon, S.E. Nelson, and E.E. Ziegler (1983), "Dietary Intake of Lead and Blood Lead Concentration in Early Infancy," Am. J. Dis. Child., 137:886-891.

6. Marcus, A.H. (1985), "Multicompartment Kinetic Models for Lead: I. Bone diffusion models for long-term retention," Environ. Research, 36:442-458.

7. Marcus, A.H. (1985), "Multicompartment Kinetic Models for Lead: II. Linear kinetics and variable absorption in humans without excessive lead exposure," Environ. Research, 36:459-472.

8. Marcus, A.H. (1985), "Multicompartment Kinetic Models for Lead: III. Lead in blood plasma and erythrocytes," Environ. Research, 36:473-489.

9. Agency for Toxic Substances and Disease Registry (1993), Toxicological Profile for Lead, U.S. Dept. of Health and Human Services, Public Health Service, Atlanta, Ga., p. 98.

10. Keough, J.P. (1992), "Lead," In: Hazardous Materials Toxicology: Clinical principles of environmental health, ed. J.B. Sullivan Jr. and G.R. Krieger, Baltimore, Md., Williams and Wilkins, p. 834.

11. U.S. Consumer Product Safety Commission (January 3, 1994), Press Release #94-021, Office of Information and Public Affairs, Bethesda, Md.

12. Public Law 86-613, 74 Stat. 372 (July 12, 1960), as amended.

13. U.S. Consumer Product Safety Commission (April 14, 1994), Hazard Assessment Procedures for Lead in Crayons: Testing for lead in crayons and assessing the hazard presented by any crayons which contain in excess of 0.01% (w/w) lead, Bethesda, Md.

14. U.S. Consumer Product Safety Commission (March 22, 1994), Press Release #94-049, Office of Information and Public Affairs, Bethesda, Md.

15. Public Law 100-695, 15 U.S.C., [section] 1277.

Corresponding author: Patricia Arreola, Epidemiology Specialist, Arizona Department of Health Services, Office of Environmental Health, 3815 North Black Canyon Highway, Phoenix, Arizona 85015. Phone: [phone].