Drone view of train derailment.

Last month’s oil spill from a string of derailed tanker cars in northwest Iowa may not have been as bad as first thought.

Clean-up is still underway near Doon where flooding evidently led to the derailment of 32 tanker cars on June 22nd. Officials with BNSF Railway now say it appears ten cars leaked oil for a total of 160,000 gallons. The original estimate was 14 cars and 230,000 gallons. The railroad says testing of nearby private wells and the Rock Valley city wells finds no contamination of drinking water.

Most of the oil coated a corn field and the topsoil, which BNSF is working to replace, though the process may take well into fall