smoke (1 hr/d, 5 d/wk for 20 wk) had a statistically significant trend in the prevalence of alveologenic carcinoma, with the frequency of this tumor reaching significance in the high-dose group at 13 mo postexposure. However, the effects cannot be attributed to zinc oxide because the smoke contained a number of other chemicals, including carbon tretrachloride, which is known to be an animal carcinogen.

No studies were found that investigated the neurological effects of zinc oxide and boric acid following inhalation exposure.

U.S. Borax (1996) lists an acute oral LD₅₀ for zinc borate in male rats of>10 g/kg.

A summary of oral toxicity studies on zinc compounds is presented in Table 8–2. When considering the oral toxicity of zinc compounds, it is important to note that zinc is an essential nutrient. NRC (1989) established recommended dietary allowances for zinc of 15 mg/d for males and 12 mg/d for females. However, chronic supplementation of more than 15 mg/d is not recommended without medical supervision because zinc can aggravate copper deficiency in individuals who are already marginally copper deficient (NRC 1989).

No human studies report death following ingestion of high zinc concentrations and toxicity normally occurs only after ingestion of more than 2 grams of zinc (Prasad 1976, as cited in ATSDR 1994; NRC 1989).

Vomiting, abdominal cramps, and diarrhea have been observed following ingestion of high levels of zinc sulfate. A wk after an English school girl ingested 440 mg zinc sulfate-d (2.6 mg zinc/kg-d) in capsules (a medically prescribed treatment for acne), she was admitted to the hospital, diagnosed with anemia, and had indications of gastrointestinal bleeding (Moore 1978). Gastrointestinal

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)