WASHINGTON (Reuters) - The U.S. Environmental Protection Agency is aiming to allow farmers to spray the controversial weed-killer dicamba next year, but with additional rules for its use, an official with the agency said on Tuesday.

Reuben Baris, acting chief of the herbicide branch of the Environmental Protection Agency’s (EPA) Office of Pesticide Programs, said the agency had not yet determined what steps it would take to mitigate problems associated with dicamba. The herbicide, which fights weeds resistant to another herbicide called glyphosate, was linked to widespread crop damage this summer.

The EPA has been discussing with state regulators ways to prevent such crop damage.

Use of dicamba, which is produced by BASF SE and Monsanto Co, spiked after U.S. regulators last year approved a new formulation that allowed farmers to apply it to soybean plants that were engineered to resist the chemical while it killed weeds. Previously it had been sprayed on fields prior to planting.

Farmers say the chemical caused damage by drifting away from where it was sprayed to fields of soybeans and other plants that could not tolerate it.

Baris told a meeting of state regulatory officials in Washington, D.C., that the agency was “very concerned with what has occurred and transpired in 2017.”

“We’re committed to taking appropriate action for the 2018 growing season with an eye towards ensuring that the technology is available, number one, to growers but that it is used responsibly,” he said.

The EPA is in negotiations with Monsanto and BASF, which sell dicamba herbicides under different brands, to make changes regarding how they are used, Baris said.

State regulators previously told Reuters the EPA was considering establishing a set date after which the spraying of dicamba weed killers on growing crops would not be allowed.

Arkansas is independently weighing an April 15, 2018, deadline.

But Tony Cofer of the Alabama Department of Agriculture, who attended the meeting, said such a cut-off date would not match Baris’ goal of maintaining dicamba’s usefulness.

“That type of restriction would not be something they’re probably considering, in all practicality, if they wanted to continue use of the product,” said Cofer, director of the Pesticide Management Division at the state’s agriculture department.

Monsanto has said the April 15, 2018, date would amount to a ban in Arkansas because the chemical was designed to be sprayed over the genetically engineered crops during the summer growing season.

Arkansas previously blocked sales of Monsanto’s dicamba herbicide in the state.