Naphthalene

Reference Dose for Oral Exposure (RfD) (PDF) (32 pp, 102 K) Last Updated: 09/17/1998

Reference Concentration for Inhalation Exposure (RfC) (PDF) (32 pp, 102 K) Last Updated: 09/17/1998

Weight of Evidence for Cancer (PDF) (32 pp, 102 K) Last Updated: 09/17/1998

• Using criteria of the 1986 Guidelines for Carcinogen Risk Assessment, naphthalene is classified in Group C, a possible human carcinogen. This is based on the inadequate data of carcinogenicity in humans exposed to naphthalene via the oral and inhalation routes, and the limited evidence of carcinogenicity in animals via the inhalation route. Using the 1996 Proposed Guidelines for Carcinogen Risk Assessment, the human carcinogenic potential of naphthalene via the oral or inhalation routes "cannot be determined" at this time based on human and animal data; however, there is suggestive evidence (observations of benign respiratory tumors and one carcinoma in female mice only exposed to naphthalene by inhalation [NTP, 1992a]). Additional support includes increase in respiratory tumors associated with exposure to 1-methylnaphthalene.
• This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (32 pp, 102 K)

Not assessed under the IRIS Program.

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (32 pp, 102 K)

Not assessed under the IRIS Program.