Chlorophenoxy herbicides causing

TCDD is the most potent inducer of chloracne. This has been well known since the accident in Seveso, Italy, in 1976 in which large amounts of TCDD were distributed in the environment subsequent to an explosion in a factory that produced a chlorophenoxy herbicide, 2,4,5-T. TCDD is an impurity produced during the production of 2,4,5-T. The most common long-term effect of TCDD exposure was chloracne. Exposed individuals also suffered increased excretion of porphyrins, hyper-pigmentation, central nervous system effects, and liver damage and increased risk of cancer was a long-term consequence of the exposure. In addition to TCDD, polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans, and polychloronaphthalens cause chloracne as well as other effects typical of TCDD. 7i... 

Kogevinas M, Saracci R, Winkelmann R, et al. 1993. Cancer incidence and mortality in women occupationally exposed to chlorophenoxy herbicides, chlorophenols, and dioxins. Cancer Causes and Control 4 547-553. 

Chronic exposure to some common chlorophenoxy herbicides such as 2,4-D through drinking water can potentially cause damage to the nervous system, kidneys, and liver. Chronic exposure to 2,4-D has also been linked to immune system suppression and endocrine disruption. Carcinogenic potential of these herbicides is not clear. 2,4-D and MCPA, which are commonly used in wheat production, have been linked to birth defects. 

Chlorophenoxy herbicides are, by themselves, of relative low toxicity to humans. They are, however, often contaminated with dioxins, of which, 2,3,7,8-tetrachloro-p-dioxin (TCDD) is the most toxic, which cause CNS and peripheral nervous system neuropathies. l8l... 

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