Third, the toxicity information that is available (for example, reference doses (RfDs) and reference concentrations (RfCs) is expressed in terms of the applied amount—not in terms of the amount that is available inside the body to cause toxicity. The difference in absorption with each route makes the route-to-route extrapolations more uncertain.

Finally, potential exposures to FRs applied to furnishing fabrics within the home have not been studied. Thus, there is little basis for estimates of exposure to such materials. There are few, if any, measurements of exposures under relevant conditions of exposure, and the subcommittee located no quantitative measurements of such exposures.

The volume of literature related to residential pesticide exposures was reviewed but not considered relevant because pesticides are not ordinarily applied to fabrics during the manufacturing process. The effectiveness of pesticides is not dependent on their ability to remain in the fabric during use. The subcommittee does not believe that using the small amount of pesticide data that might relate to fabrics would reduce uncertainty. The subcommittee believes that pesticides are not good surrogates for FR chemicals.

To make progress, therefore, the subcommittee adopted some extremely conservative assumptions (that is, corresponding to high concentration and exposure conditions) about potential exposures. In these estimations, the subcommittee determined whether each FR chemical would pose an acceptable risk even with such assumptions. If the risk was acceptable, then that chemical could be dropped from further consideration. Subsequent iterations of the procedure would then depend on finding more defensible information about the exposure conditions. The subcommittee was unable to find any such information and recommends collection of such information—a process that should be relatively straightforward but is outside the subcommittee’s charge.

People can come in contact with furnishing fabrics through direct contact (for example, by sitting on them). However, most of the time the contact is likely to be very small because of the presence of clothing and because the FR is incorporated into the fabric fiber structure or is present in a backcoating formulation added on the reverse face of the fabric. Young children, in particular, might suck on furnishing fabrics; therefore, possible dissolution in saliva and ingestion of the FRs present must be considered unless they can be demonstrated to remain “locked” within the fibers or in the backcoating resin formulation. Finally, as fabrics wear they can shed small fibers, the majority of which are likely to be too large to be inhaled to any substantial degree. However, some inhalation exposure of FR chemical species could result from the generation of particles of respirable size (≤10 µm).

Actual exposures to FR chemicals applied to fabrics are likely to be limited by multiple factors. FR chemicals are of little use unless they stay in the

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)