Carcinogenicity
In 1987 carbaryl assessment by the International Agency for Research on Cancer (IARC) concluded that there were no data on cancer in humans and that the evidence of carcinogenicity in experimental animals was inadequate. This was reinforced in 1994 by a WHO Task Group report which concluded that most of the numerous cancer studies involving rats and mice were old and did not meet contemporary standards. The Group was aware that a pesticide company was carrying out new studies. Although they had not seen all the results, the Group was informed that these studies indicated significant increases in tumours at the highest dose in both rat and mice species. One of the main recommendations from the WHO report included a request that carcinogenicity studies meeting modern standards should be conducted(13).
In the UK, in November 1995, new company data indicated carbaryl could cause cancer in humans, although the research is not yet in the public domain. The studies were assessed by the Committee on Carcinogenicity and the Advisory Committee on Pesticides, which, in reporting to the government, concluded that it would be"prudent to consider carbaryl as a potential human carcinogen"(14). The principal government response concerned the use of carbaryl against head lice in children. As a result, medicinal uses will only be available on prescription (see PN30 p.4).