Pesticide Endosulfan Ruled “Highly Toxic”

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FMC chemical plantAn international scientific review committee ruled last week that endosulfan, a widely used pesticide, is highly toxic to humans and wildlife.

The ruling concludes debate on whether the chemical should be classified as a persistent organic pollutant (POP), a decision that could result in a global ban.

"Thankfully the science - rather than political and economic interests - has been at the fore, and now there is a clear body of experts who support endosulfan's eradication as a POP," said Juliette Williams, founding director of the London-based Environmental Justice Foundation.

Endosulfan has been linked to mental retardation and death among farm workers, especially in circumstances when the chemical was applied excessively or improperly. Reproductive health effects and kidney failure have also been observed among those exposed at lower concentrations.

In the Arctic, bird, marine mammal, and fish populations are accumulating endosulfan in their fat cells. The chemical is able to travel long distances via wind and water currents, a characteristic trait of POPs.

Endosulfan is now one step away from inclusion in the Stockholm Convention on Persistent Organic Pollutants, the international treaty that enforces bans on poisonous pesticides and other toxic chemicals.

Once the review committee evaluates the socio-economic impact of phasing out endosulfan, international negotiators will meet in May 2011 to decide appropriate control measures.

At least 10,000 metric tons of endosulfan are still produced each year and applied on fruits, vegetables, and grains in some 30 countries. The substance is currently being phased out in about 60 countries, including those in the European Union, Thailand, and Niger, according to Karl Tupper, coordinator of Pesticide Action Network (PAN)-North America's environmental monitoring program.

"A dwindling number of countries are actively using endosulfan," Tupper said. "The U.S. and Canada are in the midst of a re-evaluation of the chemical.... We're pretty confident the U.S. is going to ban it by the end of this year."

India's representative to the POPs review committee was the lone opponent of listing endosulfan as a POP. The Indian delegation has accused the European Union, the main proponent of an endosulfan ban, of targeting the chemical in order to promote the European pesticide industry's patented products.

The Indian delegation also raised questions about the scientific evidence of endosulfan's toxicity, although Tupper said that the representatives were supporting their argument with studies produced more than 20 years ago.

"India's influence has been unfortunate in that it has, to a degree, politicized a process which is meant to be based on science," Williams said.

India is among the world's leading producers, exporters, and consumers of endosulfan. The government also owns Hindustan Insecticides, Ltd., a major endosulfan producer. 

Due to India's financial interest in continuing endosulfan use, environmental groups including the International POPs Elimination Network (IPEN) and PAN requested that the country recuse itself from the committee's decision.

"Most delegates were blissfully unaware of the conflict of interest," said Mariann Lloyd-Smith, a senior advisor to the Australia-based National Toxics Network Inc. and an IPEN co-chair.

Nine pollutants were added to the Stockholm Convention in May, the first new toxics included in the treaty since a group of chemicals known as "the dirty dozen" was first banned in 2001.

In addition to the endosulfan ruling, the review committee agreed to evaluate whether the flame retardant HBCD, used primarily in thermal insulation foams, qualifies as a POP.

Ben Block is a staff writer with the Worldwatch Institute. He can be reached at

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