Below are the procedures followed by the CPSC staff in testing for lead in crayons and assessing the hazard presented by any crayons which contain in excess of 0 01 percent (w/w) lead. The hazard assessment is based on the amount of extractable lead found and the assumption that a child will ingest a total of 14 grams of crayon per month consumed randomly from the package of crayons.

At the present time, packages of crayons providing in excess of 15 ug/day intake of available lead, based on the attached procedures and criteria, are considered hazardous and therefore banned hazardous substances under the Federal Hazardous Substances Act. While not necessarily banned at this point, the Commission staff is concerned with crayons containing lower levels of lead and recommends that crayons and other children's products contain no lead.

These procedures and hazard assessment criteria represent the current policy of the Commission staff and are based solely on information available to the staff at this time. The procedures and assessment criteria could be changed if the facts change, and could be changed or superseded by the Commission.

Screening:

The total lead level of individual crayons are measured after hot nitric acid digestion and inductively-coupled emission spectroscopy analysis (AOAC Method 5 009). Crayons with a total lead greater than 0 01% (w/w, limit of detection) undergo extraction for available lead.

Available lead:

Crayons above 0 01% (w/w) lead are finely shaved and extracted with dilute hydrochloric acid at 370 C (EN-7 1, ASTM Practice F 963, 8 3). This is done at a ratio of I g crayon per 50 ml extractant. A one-hour extraction is followed by a two hour extraction, and then a three-hour extraction, with complete replacement of extractant each time. The micrograms (ug) of available lead per gram (g) of crayon is the sum of the levels found in the extractants multiplied by the dilution factor of 50.

Exposure:

The Human Factors Division in CPSC indicates that a child could eat the equivalent of one large crayon found in a 12-pack of crayons over a period of one month. The amount of available lead contained in a whole crayon is the available lead per g of crayon multiplied by 14 g, which is the approximate weight of a large crayon in a 12-pack.

Assuming that a child consumes randomly from the 12 crayons, with one crayon containing detectable lead and the other I I crayons having undetectable levels of lead, the amount of lead exposure would be the amount of available lead in the single 14 g crayon divided by 12 (1 e , the available lead in about 1 2 g of that crayon would be ingested). This number is then converted from a monthly to an estimated daily intake by dividing by 30 days. The daily intake is additive when more than one crayon in a set of 12 contains lead, i e , the one-, three-, and six-hour extractions from all crayons found to have detectable lead are added, and this total is adjusted by the factor 14/(12 x 30).

If a child eats an entire leaded crayon, then the available lead in a 14 g crayon would not be divided by 12. Although consumption of only the leaded crayon was considered unlikely by Human Factors, it is possible since CPSC staff has a report of a child eating a whole crayon. This would be close to a "worst case" situation.

In the case of crayons of different sizes or different number of crayons per pack, the same amount of crayon is assumed to be eaten, i e , 14 g over a month. Thus, if a three-pack of crayons is involved, about 4 7 g of each crayon is assumed to be eaten over the period of a month. In this situation, the sum of the total extractable lead in all crayons is adjusted by the factor 14/(3 x 30). Similarly, for a 64-pack, the adjustment factor would be 14/(64*30).

Hazard level:

Directorate for Health Sciences staff estimated that a greater than 15 ug/day intake of available lead could cause a previously normal child to exceed a 10 ug/dl blood level. Considerations by the staff in developing the 15 ug/day level included estimated blood lead levels due to "normal" sources, increased lead absorption by young children compared to adults, and the relationship of intake and blood lead levels. A blood lead level above 10 ug/dl places a child at risk for serious, adverse health effects according to the Centers for Disease Control and Prevention, CPSC staff, and several other Federal agencies. Ten ug/dl is not a threshold blood lead level for adverse health effects.

Intake levels below 15 ug/day contribute to the elevation of a blood lead level along with other lead sources. Contributions less than 15 ug/day are still of health concern. A child with a marginal blood lead level could be pushed above 10 ug/dl when exposed to an additional lead source, such as leaded crayons.

Sample Calculations:

1) In a 12-pack of crayons, two crayons have detectable lead. For these two crayons, the 1-, 3-, and 6 hour extractable values are:

The total extractable lead in the two crayons is equivalent to 50 ml/g crayon * 16 ug/ml = 800 ug/g crayon. This is adjusted by the factor 14 g /(12*30 days), which is about 31 ug/day. Since this is above 15 ug/day, this package of crayons is considered to be a hazardous product.

2) In a 64-pack of crayons, three crayons have detectable lead. For these three crayons, the 1-, 3-, and 6-hour extractable values are:

The total extractable lead in the three crayons is equivalent to 50 ml/g crayon * 21 ug/mI = 1050 ug/g crayon. This is adjusted by the factor 14 g /(64*30 days), which is about 7 7 ug/day Since this is below 15 ug/day, this package of crayons is not considered to be a hazardous product. Again, however, intake below 15 ug/day still contributes to the elevation of blood lead levels along with other lead sources. Thus, contributions less than 15 ug/day are still of health concern.