Three years ago this month Monsanto executives realized they had a big problem on their hands.

It was September 2014 and the company’s top-selling chemical, the weed killer called glyphosate that is the foundation for Monsanto’s branded Roundup products, had been selected as one among a handful of pesticides to undergo scrutiny by the World Health Organization’s International Agency for Research on Cancer (IARC). Monsanto had spent decades fending off concerns about the safety of glyphosate and decrying scientific research indicating the chemical might cause cancer or other diseases. And even though the IARC review was still months away, Monsanto’s own scientists knew what the outcome would likely be—and they knew it wouldn’t be good.

Internal company records show not just the level of fear Monsanto had over the impending review, but notably that company officials fully expected IARC scientists would find at least some cancer connections to glyphosate. Company scientists discussed the “vulnerability” that surrounded their efforts to defend glyphosate amid multiple unfavorable research findings in studies of people and animals exposed to the weed killer. In addition to epidemiology studies, “we also have potential vulnerabilities in the other areas that IARC will consider, namely, exposure, genetox and mode of action…” a Monsanto scientist wrote in October 2014. That same email discussed a need to find allies and arrange funding for a “fight”—all months before the IARC meeting in March 2015.

And Monsanto predicted internally before IARC even met that the review of the scientific evidence would result in a decision that glyphosate “possibly” was carcinogenic or “probably” was. Monsanto officials had forecast the IARC decision in an internal “preparedness” plan that warned colleagues to “assume and prepare for the outcome…” The document shows Monsanto thought it most likely that IARC would peg glyphosate as a “possible human carcinogen.” The rating of probable carcinogen was “possible but less likely,” the Monsanto memo stated. IARC ultimately did classify glyphosate as “probably carcinogenic to humans.”