ST. PAUL (AP) - Minnesota regulators are considering banning or restricting insecticides that have been linked to honeybee deaths amid population decline.

The state Department of Agriculture disclosed the possibility of restrictions in a revised outline for a study of the chemicals. More than 400 people wrote to the agency earlier this year about a review proposal that didn't explicitly include a ban option.

The review is expected to take more than six months.

The state Legislature ordered the agency to devise guidelines for protecting the insects in 2013. The number of bees and other pollinators in Minnesota and across the U.S. has dropped significantly in recent years.

The U.S. Environmental Protection Agency is also reviewing the effects of the chemicals on pollinators.