About 20 people were sickened and three sent to area hospitals Sunday afternoon when an insecticide was accidentally released at the Paramount Farms warehouse facility near Lost Hills, according to the Kern County Fire Department.

Workers exposed to the chemical, called Endure, complained of trouble breathing. Most of those exposed refused treatement and left on their own, according to Fire Department spokesman Anthony Romero.

Those hospitalized had "minor conditions," Romero said.

The incident happened about 3 p.m. and Romero said it was unclear to fire fighters which building the release occurred in as the facility is made up of multiple buildings.

"The scene was turned over to Paramount Farms safety crews who will be working throughout the night trying to figure out what happened," he said.