Overview
This OECD Working Party on Exposure Assessment (WPEA) document compiles parameters and algorithms for estimating children’s chemical exposure via dermal, inhalation, and oral routes from seven craft/toy product categories: modelling clay/silly putty/slimes; paint (craft, face, finger); markers/highlighters/pens; cuddle toys/squishies; glues/adhesives/pastes; temporary tattoos; chalk/crayons/colouring pencils. Includes 12 case studies (Crayon-Oral, Markers-Dermal-Oral-Inhalation, Glue-Dermal-Oral-Inhalation, Face Paint-Dermal, Face Paint-Dermal-Oral, Finger Paint-Dermal-Oral, Slime-Dermal-Oral [×3], Putty-Dermal-Oral, Squishies-Dermal-Inhalation, Temporary Tattoos-Dermal). The document does not include analytical occurrence data on heavy metals; it is a methodology and exposure-modeling guidance.
Key numbers
- Product categories covered (Exec Summary p. 7): modelling clay/putty/slime; paint (craft/face/finger); markers/highlighters/pens; cuddle toy/squishy; glues/adhesives/pastes; temporary tattoos; chalk/crayons/colouring pencils.
- Emerging product categories examined (Section 3): kinetic sand and thinking putty; water gel, jelly marbles, and fake snow powder; Science kits and “make your own cosmetics” kits.
- Age groups for craft/toy exposure (Table 2.1, p. 14): the table lists product-by-age pairings — 0-5 months (teething ring, cuddle toy, cloth book, mobiles, push/pull toys, stuffed toys), 6-11 months (plastic doll, crayons), 1 year (modelling clay, finger paint, dress-up materials, art/construction paper, interlocking building materials), 3 years (face paint, hobby paint, slime, glue, glitter glue, marker pens, acrylic paint, squishy toy), 4-8 years (chalk, poster paint, felt pen, ball pen, life-sized dolls). Footnoted to Bremmer & van Veen 2002, Danish EPA 2015/2016/2018, and CPSC 2020. Body-weight, surface-area, and inhalation-rate defaults are flagged as outside the case-study scope and would need to be drawn from referenced regulatory factbooks (US EPA EFH 2011, RIVM General Fact Sheet).
- Case studies (Annex C, pp. 54-65): twelve worked exposure-dose calculations (A-L), each covering one product-category × route combination. Face Paint-Dermal (Case D, ages 3-6, ConsExpo dermal-direct-contact model) and Face Paint-Dermal-Oral (Case E, ages 0.5-4, ConsExpo v4.1 dermal + oral) are the most directly relevant for heavy-metal craft/cosmetic exposure modeling.
- Case A (Crayon-Oral) and Case H (Slime-Dermal-Oral) are the two case studies labelled “inorganic” in the OECD annex. Case A applies the framework to copper exposure from a 2009 MSDS-reported aqua-coloured crayon (0.3% Cu) at PA 8 mg/day, F 1/day, BW 15.5 kg, age 0.5-4 yr (illustrative MSDS-derived concentration, not a peer-reviewed occurrence value). Five additional case studies are labelled “Organic/Metal” — Case D (Face Paint-Dermal, 3-6 yr), Case F (Finger Paint-Dermal-Oral, 1-2 yr), Case G (Slime-Dermal-Oral, 3-6 yr), Case I (Slime-Dermal-Oral, up to 14 yr), Case J (Putty-Dermal-Oral, 3-6 yr) — meaning the worked formulas accept either organic or metal substance inputs but the specific substance is left product-specific rather than tied to a heavy-metal value.
- Case H (Slime-Dermal-Oral, inorganic) references the EN 71-3 element-migration test (illustrative boron migration up to 6,384 mg/kg) under the BfR (2022) opinion framework. EN 71-3 is the Toy Safety Directive 2009/48/EC analytical reference for migration of Pb, Cd, As, Sb, Ba, Hg, Se, Cr, and other elements; the case study uses the same migration framework with boron as the worked-example analyte.
- Case studies submitted by 4 WPEA contributors (Netherlands, Germany, Canada, Denmark) per Executive Summary p. 7. Broader subgroup membership (Australia, Canada, Costa Rica, France, Germany, Italy, Japan, Korea, Netherlands, Sweden, US, EU, BIAC, WHO, EEB) reviewed the document per Foreword.
- Endorsed by OECD WPEA June 2024; published under Chemicals and Biotechnology Committee responsibility.
Methods (brief)
OECD WPEA-led methodology compilation. Sources reviewed: existing exposure-modeling tools and frameworks from US EPA (ExpoFIRST, SHEDS, EPA Exposure Factors Handbook 2011), EU ECHA (ECETOC TRA, ConsExpo, BfR exposure models), Health Canada (ConsExpo-Web), and peer-reviewed exposure-science literature. Approach: for each of the seven product categories, the document lists existing default parameters (mass per use, frequency, duration, surface area exposed, inhalation rate, room volume) and recommended algorithms (one-compartment dermal, fraction-released oral, instantaneous-release inhalation). Each case study includes source documentation for default values, calculated dose, and identified data gaps. Limitations stated: emerging products (kinetic sand, water gel marbles, science kits) lack dedicated exposure parameters; observational data on children’s actual use patterns are scarce; inter-individual variability in body weight, skin surface area, inhalation rate, and use duration is high.
Implications
- Certification (HMTc): Methodology reference for face-paint and finger-paint exposure modelling. Case D (Face Paint-Dermal, ConsExpo direct-contact, 410 cm² exposed half-head area, 1.2 g product amount, 12 applications/year, 15.7 kg BW) and Case E (Face Paint-Dermal-Oral, ConsExpo v4.1, 1.4 g/application, 0.44 mg/min oral ingestion rate, 480 min duration) supply default exposure parameters that can be combined with heavy-metal occurrence data from other sources to estimate per-event dose. Not directly threshold-anchoring (no occurrence values in this document).
- Courses: Foundational regulatory-affairs reading for children’s product exposure-assessment modules. Demonstrates the OECD-harmonized framework for craft/toy exposure estimation across dermal, oral, and inhalation routes.
- App: Not relevant to ingredient contamination_profile. Provides per-product use-frequency and use-duration defaults that could seed a children’s-product use-pattern table.
Related evidence
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