National Toxicology Program

National Toxicology Program
https://ntp.niehs.nih.gov/go/21283

Nominations Reviewed 2000

Chemicals studied by the NTP are selected mainly on the basis of human exposure, production levels, chemical structure, and available toxicological data. Selection of an agent for a study does not imply that the agent is hazardous or a potential carcinogen in laboratory animals; likewise, an agent not selected for toxicologic study by the Program should not be taken to mean that the agent is not potentially hazardous or potentially carcinogenic in laboratory rodents. Substances are identified by a common or generic name and CAS Registry No. where appropriate.

For information, questions or comments, contact:

Dr. Scott A. Masten
Director, Office of Nomination and Selection
Division of the National Toxicology Program
National Institute of Environmental Health Sciences

P.O. Box 12233, MD K2-02
Research Triangle Park, NC 27709
(919) 541-5710 (voice)
(301) 451-5599 (fax)

[Send Email]

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Aluminum Complexes found in drinking water
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Aluminum Complexes found in drinking water
  • Aluminum fluoride
    [7784-18-1]
  • Aluminum citrate
    [31142-56-0]
  • Environmental Protection Agency
  • National Institute of Environmental Health Sciences
Drinking water contaminants with a high health research priority; known neurotoxicity of aluminum; need for better understanding of pharmacokinetics and toxicity of aluminum species occurring in drinking water
  • Long-term drinking water studies to address pharmacokinetics, neurotoxicity, bone development, and reproductive and developmental toxicity
  • Consider testing in transgenic animal models of neurodegenerative disease

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Bilberry fruit extract
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Bilberry fruit extract
[84082-34-8]
National Cancer Institute
  • widespread human exposure through use as a dietary supplement
  • lack of toxicity information
In vitro and in vivo genotoxicity testing

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Black Cohosh
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Black cohosh
[84776-26-1]
  • National Cancer Institute
  • National Institute of Environmental Health Sciences
  • widespread human exposure through use as a dietary supplement
  • reported estrogenic activity
  • inadequate toxicity information
  • subchronic toxicity testing in young and aged female animals
  • Two-generation reproductive and developmental toxicity study

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Blue-Green algae (dietary supplements and selected toxins)
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Blue-Green algae (dietary supplements and selected toxins)
[No CAS No.]
National Cancer Institute
  • widespread human exposure through drinking water and via contamination of algal dietary supplements
  • demonstrated acute toxicity but only limited chronic toxicity information available
  • subchronic toxicity and neurotoxicity studies of commercial blue-green algae dietary supplements
  • consider testing specific cyanobacterial toxins pending results of Blue-Green algae dietary supplement and microcystin-LR studies

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Cefuroxime
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Cefuroxime
[55268-75-2]
Food and Drug Administration
  • prescription drug with widespread and potentially long-term use
  • lack of chronic toxicity data for any member of this class of drugs
  • genotoxicity testing (Syrian hamster embryo in vitro cell transformation assay
  • in vivo micronucleus assay)

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Clarithromycin
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Clarithromycin
[81103-11-9]
Food and Drug Administration
  • prescription drug with widespread and potentially long-term use
  • numerous known toxicities in short-term studies
  • lack of chronic toxicity data
Genotoxicity testing (Syrian hamster embryo in vitro cell transformation assay; in vivo micronucleus assay)

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D&C Red No. 27 and D&C Red No. 28
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
D&C Red No. 27 and D&C Red No. 28
[13473-26-2],[18472-87-2]
Food and Drug Administration
  • approved colorings for drugs and cosmetics that can lead to DNA damage
  • lack of sufficient data on long-term phototoxicity or photocarcinogenicity
  • in vitro percutaneous absorption testing
  • Photocarcinogenicity testing dependent on results of absorption studies

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N,N-Dimethyl-p-toluidine
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
N,N-Dimethyl-p-toluidine
[99-97-8]
National Cancer Institute
  • high production volume chemical with potential for widespread human exposure and limited chronic toxicity or carcinogenicity data
  • genotoxic
  • suspicion of carcinogenicity
Subchronic toxicity testing pending review of industry test plans and/or data developed under EPA's High Production Volume Chemical Challenge Program

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Lemon Oil and Lime Oil
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Lemon Oil and Lime Oil
[8008-56-8],[8008-26-2]
Food and Drug Administration
  • widespread consumer exposure as a fragrance component
  • known phototoxicity
  • long-term toxicity unknown
  • photogenotoxicity testing
  • photocarcinogenicity testing dependent on results of phototogenotoxicity studies

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Local anesthetics that metabolize to 2,6-xylidine or o-toluidine
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Local anesthetics that metabolize to 2,6-xylidine or o-toluidine
  • Bupivacaine
    [38396-39-3]
  • Prilocaine
    [721-50-6]
  • Private Individual
  • National Institute of Environmental Health Sciences
  • widespread clinical use and human exposure
  • potentially metabolized to carcinogenic and neurotoxic intermediates
  • little available quantitative metabolism or genotoxicity data
Short-term in vitro/in vivo mechanistic studies to evaluate carcinogenic metabolite formation and genotoxicity of representative local anesthetic compounds

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Microcystin-LR
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Microcystin-LR
[101043-37-2]
National Institute of Environmental Health Sciences
  • cyanobacteria and their toxins are drinking water contaminants with a high health research priority
  • many have high acute toxicity and known hepatotoxicity and hepatocarcinogenicity
  • Toxicokinetic, subchronic, reproductive toxicity, chronic toxicity and carcinogenicity studies including doses relevant to environmental concentrations in drinking water
  • Consider carcinogenicity testing in Japanese Medaka fish model

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Organotins occurring in drinking water
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Organotins occurring in drinking water
  • Monomethyltin trichloride
    [993-16-8]
  • Dimethyltin dichloride
    [753-73-1]
  • Monobutyltin trichloride
    [1118-46-3]
  • Dibutyltin dichloride
    [683-18-1]
Environmental Protection Agency; National Institute of Environmental Health Sciences
  • drinking water contaminants with a high health research priority
  • numerous organotins have demonstrated a broad spectrum of toxicity
  • chronic toxicity information on organotin species primarily found in drinking water is limited
  • Long-term single chemical and binary mixture drinking water studies to address pharmacokinetics, neurotoxicity, immunotoxicity, and reproductive and developmental toxicity
  • Consider testing in transgenic animal models of neurodegenerative disease

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All-trans-retinyl palmitate
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
All-trans-retinyl palmitate
[79-81-2]
Food and Drug Administration
  • widespread use in cosmetic products
  • known biochemical and histological cutaneous alterations
  • other retinoids known to enhance photocarcinogenesis
Phototoxicity and photocarcinogenicity testing

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S-Adenosylmethionine
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
S-Adenosylmethionine
[29908-03-0]
National Cancer Institute
  • widespread exogenous human exposure through use as a dietary supplement
  • limited toxicity data available
  • In vitro genotoxicity testing (Syrian hamster embryo cell transformation and DNA alkylation assays)
  • Subchronic toxicity testing dependent on results of genotoxicity studies

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Senna
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Preliminary Study Recommendations
Senna
[8013-11-4]
Food and Drug Administration
  • data needed to complete safety evaluation of stimulant laxatives
  • transgenic studies will complement manufacturer sponsored carcinogenicity studies
Carcinogenicity testing in p53 transgenic mouse model

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Dichloropropane & Dichloropropene
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Additional Information Needed
 
Dichloropropane & Dichloropropene
  • 1,3-Dichloropropane
    [142-28-9]
  • 2,2-Dichloropropane
    [594-20-7]
  • 1,1-Dichloropropene
    [563-58-6]
Environmental Protection Agency; National Institute of Environmental Health Sciences
  • drinking water contaminants with high health research priority
  • very limited toxicity data
  • known toxicity and carcinogenicity of structurally similar compounds
  • Additional drinking water occurrence data
  • production volumes
  • potential sources of drinking water contamination
  • anticipated regulatory value of additional toxicity data

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Hydergine
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Additional Information Needed
 
Hydergine
[8067-24-1]
National Cancer Institute
  • ergot alkaloid prescription drug with recent increase in "off label" and dietary supplement use in healthy individuals
  • lack of availableinformation on toxicity and carcinogenicity
  • dietary supplement sales and use information
  • regulatory agency information needs

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Yohimbe bark extract/Yohimbine
Substance
[CAS No.]
Nominated by Nomination Rationale
(Principles)
Additional Information Needed
 
Yohimbe bark extract/Yohimbine
[85117-22-2],[146-48-5]
National Cancer Institute
  • significant human exposure through use as a dietary supplement
  • suspicion of carcinogenicity of yohimbine based on structural similarity to reserpine

  • dietary supplement use levels and patterns
  • regulatory agency information needs
NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.