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relative to the absorption and effects of minimal lead exposure in the human fetus and infant less than 12 months of age is virtually non- existent. Since studies in experimental animals indicate that the suckling animal is extremely vulnerable to the effects of lead, we feel that primary consideration should be given to examining the effects of lead in human infants less than one year of age, particularly in regard to effects in the neurologic system. CONCLUSIONS AND RECOMMENDATIONS The conclusions given below are based on what is known from studies in experimental animals and humans. Unfortunately, some factors which may influence a child's susceptibility to lead are poorly under- stood. Studies in both experimental animals and children have shown that the brain is particularly vulnerable to permanent damage if injury to the developing brain occurs during infancy. In addition, young animals and children have been shown to absorb a higher proportion of ingested lead than adults. Animal experiments have shown a higher retention of ingested lead in animals receiving lipids or milk in the diet than In those receiving dry feed. In addition, dietary deficiencies of calcium, copper, and iron increased the absorption of lead in experimental animals. No data relative to these points are available in children. However, the average child's diet contains both lipids and milk. Dietary defi- ciencies, particularly iron deficiency, have been shown to exist in a significant number of American children. No firm data are available to elucidate genetic factors which may possibly influence susceptibility to lead. Although the best available evidence suggests that some children may ingest 1 to 3 grams of paint per week, there is no basis for assuming that 3 grams of paint is the maximum amount ingested. In summary, the conclusions and recommendations, where possible, are based on known available information in children; where information is lacking, they are based on the extrapolation of data from studies in either adults or in experimental animals which most closely approximate the conditions found in preschool-age children. Conclusions 1. Since the CPSC-supplied studies did not adequately simulate the conditions found in young children, particularly in relation to age and diet, we were unable, on the basis of these studies, to determine that 0.5 percent lead in paint is safe. 2. Since the first metabolic effects in children become evident when the blood lead concentration exceeds 30 yg/dl, and since the most desirable means of controlling disease is prevention, we recommend that the total daily lead exposure, including exposure from food, ambient air and paint, for a one- to five-year-old child not exceed levels sufficient to raise the blood lead concentration above 30 yg Pb/dl. In order to allow for variations among individuals, the mean blood lead concentration for groups should not exceed 20 yg Pb/dl. Among two to three year old children an absorption of 4.5 yg/kg/day is apparently associated with a mean blood lead concentration of 20 yg/Pb/dl.
3. Since control of the lead paint hazard is difficult to accomplish once multiple layers have been applied in homes over two to three decades, and since control is more easily regulated at the time of manufacture, we recommend that a limit for the lead content of paints be set and enforced at the time of manufacture. 4. Since 0.5 percent lead in paint represents a hazard to a child with pica for paint, and since most currently available household paints contain <0.06 percent lead in paint, thus demonstrating that lead is not an essential ingredient for all paints, and since a reasonable allowance must be made for variations due to contamination of raw materials and detection limits and precision of analytical methods for analyzing the lead content of paints, we recommend that the deliberate addition of lead to paint for residential buildings or other surfaces accessible to young children be immediately discontinued and that a level not to exceed 0.06 percent lead in the final dried product be set for regulatory purposes. Since paints without lead additives may con- tain up to 0.03 percent lead, a level of 0.06 percent lead provides reasonable latitude for regulatory purposes. 5. Since a time allowance is necessary to implement these recommendations, and since extensions may be sought to delay compliance, we recommend that variances be allowed only on the basis of demonstrated economic hardship and that none be allowed to extend beyond five years. A time limit of five years will prevent accumulation of lead to dangerous levels from repeated applications. 6. Since most cases of serious childhood lead poisoning found today are clearly related to the ingestion of old lead paints, and since this hazard may be expected to exist in older homes for some time, we strongly recommend that research be conducted to determine methods for the removal of old lead paints, which will provide adequate safety for both the residents and the workmen performing the renovation procedures. 7. Since the infant is most vulnerable to the effects of lead and since little is known about the relationship between lead dose and effect in the child from birth to one year of age, we recommend that the lead content of paints or coatings on infant toys and furniture should not exceed 0.06 percent lead and that food commonly fed to infants should contain the lowest practical level of lead as determined by FDA. 8. Since few studies in experimental animals have provided adequate designs to simulate the conditions found in a young child and since no research has been conducted on the relationship between lead dose and effect in the human infant less than 12 months of age, and since few studies in preschool-age children have provided adequate information on the dose-response relationship for lead in the one- to five-year-age group, we recommend that future research focus on these areas. 9. Lead continues to have diverse uses, the regulation of which falls under numerous different governmental agencies depending on 10
its use. We recommend that these various agencies coordinate their research efforts in relation to the dangers of lead and that they coor- dinate their policies regarding the limits for human exposure from industrial sources, consumer products, air, food and water so that an individual's total exposure from various sources falls within a range which allows a margin of safety for those individuals in the population who are affected by relatively low doses. ll
