Roundup Safety Concerns May Lead California to Label Weed Killer a “Cancer Causing” Compound

Amid continuing concerns about the link between exposure to the weed killer Roundup and cancer, California may become the first state to require label warnings that indicate the key ingredient in the herbicide, glyphosate, is a cancer-causing agent. 

The California Environmental Protection Agency’s (CAL-EPA) Office of Environmental Health Hazard Assessment (OEHHA) issued a notice of intent this month, which warns that it has decided to list glyphosate as a chemical that is known to cause cancer. In addition, the OEHHA will also be adding tetrachlorvinphos, parathion, and malation to that list as well.

Roundup is one of the most widely used herbicides, which was introduced by Monsanto in the 1970s. However, concerns have emerged in recent months about the potential Roundup cancer risks associated with glyphosate exposure, after the World Health Organization’s International Agency for Research on Cancer (IARC) issued a warning in March about the potential human health side effects of the chemical.

According to the OEHHA notice, the IARC monograph (PDF) on glyphosate and its reports on the other chemicals meet the state’s criteria for listing them as carcinogens on a state-wide level. The state is accepting public comment on the notice until October 20.

If the move goes forward, there will not be any restriction on sales or use of Roundup. However, Monsanto would be required to add a “clear and reasonable” health warning to Roundup products sold in the state.

Monsanto has said that the IARC’s conclusions were agenda-driven and based on “junk science,” and has indicated it is convening its own independent panel to review the cancer risks of Roundup.

Consumer use of Roundup began to skyrocket in the mid 1990s, after Monsanto introduced genetically engineered crops to withstand treatment with Roundup, killing the weeds and not the crops. Genetically modified crops, like corn and soybean, are branded as being “Roundup Ready.” Some weeds have developed resistance to glyphosate, thus forcing farmers to use higher quantities of Roundup.

The U.S. Geological Survey estimated agricultural use of glyphosate increased drastically from 110 million pounds in 2002, now to more than 283 million pounds in 2012.

The U.S. Environmental Protection Agency (EPA) announced in April that it plans to address the safety concerns of glyphosate during the regular EPA safety review hearing occurring soon. Researchers warn pesticides are commonly detected in the air, food and water near areas that have been sprayed.