Changes

==Classification==

==Classification==

There are two main ways in which carcinogens are classified.  The main classification is produced by the International Agency for Research on Cancer, the other by the National Toxicology Program.

Carcinogens are classified by the International Agency for Research on Cancer and the National Toxicology Program.

===International Agency for Research on Cancer===

===International Agency for Research on Cancer===

The [[International Agency for Research on Cancer]] (IARC), which is part if the [[World Health Organization]], produces the most widely used system for classifying carcinogens in its ''Monographs'', published since 1971.<ref>http://monographs.iarc.fr/index.php</ref>  Substances are classified by IARC as to their carcinogenic hazard to humans: ''Established'', ''Probable'', ''Possible'',  ''Unclassifiable'', and ''Not probable''.<ref>IARC: [http://monographs.iarc.fr/ENG/Classification/index.php Classifications]</ref>  The group qualifiers ''probable'' and ''possible'' have no [[quantitative]] significance but are used as descriptors of different levels of evidence of human carcinogenicity.<ref>Group [http://monographs.iarc.fr/ENG/Preamble/currentb6evalrationale0706.php definitions].</ref>

The [[International Agency for Research on Cancer]] (IARC), of the [[World Health Organization]], produces the most widely used system<ref name="ACS"/> for classifying carcinogens in its ''Monographs'' (published since 1971<ref>http://monographs.iarc.fr/index.php</ref>). Substances are classified by IARC as to their carcinogenic hazard to humans: ''Established'', ''Probable'', ''Possible'',  ''Unclassifiable'', and ''Not probable''.<ref>IARC: [http://monographs.iarc.fr/ENG/Classification/index.php Classifications]</ref>  The group qualifiers ''probable'' and ''possible'' have no [[quantitative]] significance but are used as descriptors of different levels of evidence of human carcinogenicity.<ref>Group [http://monographs.iarc.fr/ENG/Preamble/currentb6evalrationale0706.php definitions].</ref>

===National Toxicology Program===

===National Toxicology Program===

The [[National Toxicology Program]], part of the [[U.S. Department of Health and Human Services]], classifies carcinogens in two categories: ''Known'', and ''Reasonably anticipated''.<ref name="NTP">National Toxicology Progam: [http://ntp.niehs.nih.gov/index.cfm?objectid=03CA6383-9766-1F64-6637241FE0114FE9 Questions & Answers about the RoC].</ref>  Since 1978, it has produced a list of carcinogenic material along with federal regulations limiting exposure.<ref name="NTP"/>

The [[National Toxicology Program]] (NTP), of the [[U.S. Department of Health and Human Services]], classifies carcinogens in two categories: ''Known'', and ''Reasonably anticipated''.<ref name="NTP">National Toxicology Progam: [http://ntp.niehs.nih.gov/index.cfm?objectid=03CA6383-9766-1F64-6637241FE0114FE9 Questions & Answers about the RoC].</ref>  Since 1978, it has produced a list of carcinogenic material along with federal regulations limiting exposure.<ref name="NTP"/>

 

==References==

==References==

==External Links==

==External Links==

*National Institute for Occupational Safety and Health (part of the CDC): [http://www.cdc.gov/niosh/npotocca.html Carcinogen List]

*National Institute for Occupational Safety and Health (part of the CDC): [http://www.cdc.gov/niosh/npotocca.html Carcinogen List]

*Full text to the ''[http://monographs.iarc.fr/ENG/Preamble/index.php Preamble to the IARC Monographs]''

*Full text to the ''[http://monographs.iarc.fr/ENG/Preamble/index.php Preamble to the IARC Monographs]''