Oyster harvest areas that were closed as a precaution following a huge oil spill on the Mississippi River at New Orleans have been reopened.

The state Department of Health and Hospitals says harvesting can resume a half-hour before sunrise on Thursday in three areas located in Plaquemines Parish near the mouth of the river.

Dr. Jimmy Guidry, the state’s health officer, says testing of the oyster beds in those beds revealed no contamination. He says the state will continue to monitor conditions in shellfish growing areas to make sure that remains the case.