in conjunction with other chemicals, including antimony trioxide, magnesium hydroxide, alumina trihydrate, and some brominated flame retardants. Zinc borate is used as a flame retardant on commercial furniture, draperies, wall coverings, and carpets (R.C.Kidder, Flame Retardant Chemical Association, unpublished material, April 21, 1998). In addition, zinc borate is used as a fungicide.

Zinc oxide is used as a pigment in paint, cosmetics, and dental and quick drying cements. Therapeutically, zinc oxide is used as an astringent and as a topical protectant.

Boric acid is used in enamels, porcelain, soaps, cosmetics, and as an insecticide. Therapeutically, boric acid is used as an astringent and an antiseptic.

No studies were identified that investigate the toxicokinetics of zinc borate following dermal, inhalation, or oral exposure.

Agren (1991) reported that zinc is present in human interstitial fluid at the site of application following dermal application of zinc oxide in gum resin or hydrocolloids to human forearms. No evidence for absorption into systemic circulation was provided. Zinc readily permeates intact and damaged human skin following dermal application; however, absorption of zinc into systemic circulation was not determined (Hallmans 1977; Agren 1990, as cited in ATSDR 1994; Agren et al. 1991, as cited in ATSDR 1994). Keen and Hurley (1977) determined that when zinc (as zinc chromate) was dissolved in oil and topically applied to rats, absorption of zinc into the bloodstream occurred. No other animal studies were identified that investigated the dermal absorption of zinc.

Workers exposed occupationally (via inhalation) to zinc fumes (zinc compound not specified) had elevated blood zinc concentrations (Hamdi 1969). Exposure of cats to zinc oxide fumes for up to 3.25 hr resulted in increased concentrations of zinc in the pancreas, kidney, and liver (Drinker and Drinker 1928, as cited in ATSDR 1994). In both studies, oral absorption of zinc particles following ciliary clearance and swallowing could account for all, or a

Front Matter (R1-R22)

Executive Summary (1-14)

1 Introduction (15-20)

2 Assessment of Health Risks from the Use of Flame Retardants (21-34)

3 Exposure Assessment Methodology (35-52)

4 Hexabromocyclododecane (53-71)

5 Decabromodiphenyl Oxide (72-98)

6 Alumina Trihydrate (99-130)

7 Magnesium Hydroxide (131-148)

8 Zinc Borate (149-191)

9 Calcium and Zinc Molybdates (192-228)

10 Antimony Trioxide (229-261)

11 Antimony Pentoxide and Sodium Antimonate (262-272)

12 Ammonium Polyphosphates (273-290)

13 Phosphonic Acid, (3-{[Hydroxymethyl]amino}-3-Oxopropyl)-Dimethyl Ester (291-306)

14 Organic Phosphonates (307-337)

15 Tris Monochloropropyl Phosphates (338-357)

16 Tris (1,3-dichloropropyl-2) Phosphate (358-386)

17 Aromatic Phosphate Plasticizers (387-416)

18 Tetrakis(hydroxymethyl) Phosphonium Salts (417-439)

19 Chlorinated Paraffins (440-492)

Appendix A Biographical Sketches (493-498)

Appendix B Flame-Retardant Composition in Fabrics: Their Durability and Permanence (499-512)