U.S. biotech giant Monsanto Co. agreed Thursday to pay a $2.5 million fine for misbranding its cotton-seed products, the largest civil penalty ever enforced under a federal act that controls the sale and use of pesticides.

According to the Environmental Protection Agency, Monsanto distributed cotton-seed products that contained a genetically engineered pesticide banned from 10 counties in Texas for fear pests would become resistant to it.

Monsanto was required to label the products with an explanation of the ban.

In 2007, the company disclosed to the EPA that it didn’t include notice of the ban. A subsequent EPA investigation concluded that the company sold or distributed the misbranded products between 2002 and 2007.

“The regulated community should understand that we take these violations seriously, and the public will accept nothing less than compliance,” said Cynthia Giles, assistant administrator for EPA’s office of enforcement and compliance assurance.

The company responded to the settlement by saying it has implemented a new internal review process to prevent such errors.

“We take full responsibility for this oversight, and we are committed to compliance with the terms of our EPA registrations,” said John Chambers of Monsanto in a statement.