Naphthalene

CASRN 91-20-3

Health Hazard Assessments for Effects Other than Cancer


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

RfD (mg/kg-day) System Basis PoD Composite UF Confidence
2 x10-2 Other Decreased mean terminal body weight in males NOAEL (ADJ): 7.1 x101
mg/kg-day
3000 Low

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

RfC (mg/m3) System Basis PoD Composite UF Confidence
3 x10-3 Nervous, Respiratory Nasal effects: hyperplasia and metaplasia in respiratory and olfactory epithelium, respectively LOAEL (HEC): 9.3
mg/m3
3000 Medium

Cancer Assessment


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

WOE Characterization Framework for WOE Characterization
C (Possible human carcinogen) Guidelines for Carcinogen Risk Assessment (US EPA, 1986)
Carcinogenic potential cannot be determined Proposed Guidelines for Carcinogen Risk Assessment (US EPA, 1996)
Basis:
  • 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.


Naphthalene is being reassessed.

Assessment Manager(s): Channa Keshava (keshava.channa@epa.gov), Keith Salazar (salazar.keith@epa.gov)

Step Assessment Materials Released to the Public Release Date Public Meeting Date
1 Problem Formulation Materials 07/2014 09/2014
1 Preliminary Assessment Materials TBD TBD
4 Public Comment Draft TBD TBD
4 Peer Review Draft TBD TBD
7 Post Final Assessment TBD

Please note: Any future dates displayed under Release Date are estimates and subject to change.

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