Organochlorines and organochlorides are environmental contaminants which pose threat to living organisms.

In 1962, the influential book "Silent Spring" by Rachel Carson brought the issue of organochloride toxicity to public awareness. While many countries have phased out the use of some types of organochlorides (such as the US ban on DDT as a result of Carson's work), persistent organochlorides continue to be observed in humans and mammals across the planet at potentially dangerous levels many years after production and use have been limited.

Many organochlorides have significant biological activities, and some can be toxic. For example, many powerful and effective insecticides are organochlorides. Common examples include DDT, 2,4-D, dicofol, heptachlor, endosulfan, chlordane, mirex, and pentachlorophenol. Polychlorinated biphenyls (PCBs) were once commonly used electrical insulators and heat transfer agents. Their use has generally been phased out due to health concerns, but they can still be found in our food supply due to contamination.

Sucralose, a "popular" artificial sweetener now used in more than 4,500 food products is an organochlorine.  

References

National Exposure Report: http://www.cdc.gov/exposurereport/results_08.htm