Some 600 people are on lists drawn up by the PR agency for Monsanto.
This is three times the number reported when the scandal broke last month, after revelations in French newspaper Le Monde that lists of opponents and supporters had been compiled to help the company respond to a mounting crisis over the herbicide glyphosate.
Sold by Bayer under the brand name Roundup, the weedkiller has been described as carcinogenic in numerous lawsuits.
The existence of the lists, which include details of journalists, politicians and agricultural and non-profit leaders, has prompted an investigation by the Paris Public Prosecutor's Office.
FleishmanHillard drew up lists of stakeholders in France, Germany, Italy, Netherlands, Poland, Spain and the United Kingdom, as well as "stakeholders related to EU institutions", according to Bayer.
Bayer’s press office tweeted on Monday: "Update on Monsanto's stakeholder lists: by the end of last week, the law firm commissioned by @Bayer has written to all persons on the German and French lists. In total, this is around 600."
Update zu den Stakeholder-Listen von Monsanto: Bis Ende vergangener Woche hat die von @Bayer beauftragte Kanzlei alle Personen, die sich auf den deutschen und französischen Listen befinden, angeschrieben. Insgesamt sind dies rund 600. https://t.co/XVPfkByRsB— Bayer Presse DE (@BayerPresse_DE) June 17, 2019
This comes just weeks after the pharma and life sciences company suspended its work with FleishmanHillard.
"For all ongoing activities, Bayer is examining the contractual options for a possible exit as soon as possible. Marketing projects are excluded from this decision," according to a statement on the company's website about "Monsanto’s stakeholder mapping project".
When approached for a comment on the latest developments, FleishmanHillard referred PRWeek to a lengthy statement issued by the agency’s president and chief executive, John Saunders, last month.
He claimed that "a lot of the recent attention has mischaracterised our work", and said: "Corporations, NGOs and other clients rightfully expect our firm to help them understand diverse perspectives before they engage. To do so, we and every other professional communications agency gather relevant information from publicly available sources. Those planning documents are fundamental to outreach efforts."
He added: "We work at the direction of our clients. We do so ethically and in good faith."
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