Table 4.

Reference dose (RfD) and reference dose estimates (RfD_e) for CWAs and TICs.^a

CWA or TIC	Chronic Reference dose (RfD or RfDe) (mg/kg/day) Ingestion: estimate of daily exposure level for general population; chronic exposure duration (7 yr to lifetime)
Tabunb (GA)	4 × 10−5
Sarinb (GB)	2 × 10−5
Somanb (GD) and Cyclosarinb (GF)	4 × 10−6
VXb	6 × 10−7
Sulfur mustardb (H/HD)	7 × 10−6
Hydrogen cyanidec (AC)	0.02
Cyanogen chlorided (CK)	0.05
Phosgenee (CG)	No estimate availablee

^aAdapted from Munro et al. (1999) and Talmage et al. (2007a).

^bOpresko et al. (2001). Values for nerve and sulfur mustard agents are estimates (RfD_e) and considered scientifically valid by the National Research Council (NRC/COT 1999; Bakshi et al. 2000); they have not been formally reviewed by IRIS. The value for GF is also an RfD_e and has been developed by analogy to GD.

^cUSEPA/IRIS (1993).

^dUSEPA/IRIS (2005). A comprehensive review of toxicological studies was completed in May, 2005; USEPA determined that results of review did not warrant a change in RfD at that time (http://www.epa.gov/ncea/iris/subst). CK also known as chlorine cyanide.

^eIRIS (http://www.epa.gov/iris/subst) states that phosgene oral RfD was under discussion as of January 31, 2006. There has been no change in this determination as of August 2010.