ST. LOUIS — The National Black Farmers Association filed on Wednesday a federal lawsuit to block Creve Coeur-based agribusiness giant Monsanto and its German parent company, Bayer, from selling the weedkiller Roundup.

The suit alleges that Black farmers across the country have been forced to use Roundup-resistant seeds and Roundup in increasingly heavier applications, and that Monsanto failed to inform the farmers of the weedkiller’s risks.

“The cycle can only be broken by removing the product from the market,” Chris Schnieders, a partner at Napoli & Shkolnik in Kansas City and one of the attorneys who filed suit, said at a Wednesday press conference.

In June, Bayer agreed to pay more than $10 billion to settle tens of thousands of claims that Roundup causes cancer, but wouldn’t agree to stop selling the product, or add warning labels.

Bayer said Wednesday’s suit is brought by two firms that refused to settle. “People should see this action for what it is — an attempt by plaintiffs’ lawyers to use media and more litigation to further their own financial interests,” the company said in a statement sent by deputy communications director Susan Luke.