The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Substances capable of causing cancer.
The U.S. Environmental Protection Agency (EPA) classifies many substances on the basis of their potential for causing cancer. Classifications are based on results of studies on animals, or with humans. Classification categories refer to epidemiological studies, which are studies to identify the factors controlling the presence or absence of a disease.
Group A or Human Carcinogens. There is a relationship between the substance and cancer that has been shown through epidemiological studies on humans.
Group B or Probable Human Carcinogen. There are two types of carcinogens in this category. There is sufficient evidence from animal studies and limited epidemiological studies that B1 carcinogens cause cancer. B2 carcinogens are classified on the basis of sufficient evidence from animal studies only; epidemiological data are inadequate or nonexistent.
Group C or Possible Human Carcinogens. Classification in this category is based on limited evidence from animal studies and no epidemiological data.
Group D or Not Classifiable as to Human Carcinogenicity. The studies on substances in this category are inadequate or completely lacking, so no assessment of the substance's cancer-causing potential is possible.
Group E or Evidence of Noncarcinogenicity for Humans. Substance in this category have tested negative in at least two adequate animal cancer tests in different species and in adequate epidemiological and animal studies.
U.S. Department of Health and Human Services, Public Health Service, Seventh Annual Report on Carcinogens, Summary 1994. National Institute of Environmental Health Sciences: Research Triangle Park, North Carolina, 1995. Contact the National Institute of Environmental Health Sciences Publications Office, (919) 541-3419.