The US Environmental Protection Agency (EPA) published a report on 29 April concluding that the weedkiller glyphosate is “not likely to be carcinogenic to humans” but then pulled the report offline just three days later.

The report was published on the website that the EPA manages and was from the EPA's cancer assessment review committee (CARC), Reuters said.

It was taken down on 2 May, along with other documents. In an e-mailed statement to Reuters, the EPA said the documents were "preliminary" and were published "inadvertently”, and were part of the agency’s broader registration review of glyphosate and its potential human health and environmental risks, which began in 2009.

"EPA has not completed its cancer review," it told Reuters. "We will look at the work of other governments as well as work by (the US Department of Health and Human Services') Agricultural Health Study.

The EPA said its assessment would be peer reviewed and completed by the end of 2016.

Monsanto, meanwhile, stated in a press release on 2 May that “no pesticide regulator in the world considers glyphosate to be carcinogen and this conclusion by the US EPA once again reinforces this important fact”.

Monsanto said the EPA was the third regulator to conclude glyphosate was unlikely to pose a human cancer risk following similar rulings by the European Food Safety Authority (EFSA) in November 2015 and the Canadian Pest Management Regulatory Authority in 2015.

This is in contrast to the World Health Organization’s International Agency for Research on Cancer (IARC) statement on March 2015 that glyphosate was “probably carcinogenic to humans”.

Glyphosate is the active ingredient in herbicides manufactured by Monsanto, Syngenta and Dow, which are widely used with GM crops.