The Palo Alto County Sheriff’s Office said late Friday afternoon, residents of three households that were evacuated near the site of a train derailment and fire in the northwest Iowa county have been allowed to return home. The department says the three homes were each at least a half-mile from the site, where the ethanol-fueled fire was still burning late Friday afternoon.

The derailment occurred around 1 a.m. Friday near Graettinger. It sent 27 tanker cars, each carrying 25,000 gallons of ethanol, off the tracks. The sheriff’s office says two crew members escaped unharmed. No injuries have been reported.

Iowa DNR Field office supervisor Ken Hessenius said Friday afternoon that “there was a pretty big explosion” around 2:30 p.m. at the site, but that officials expect the fire to have burned out by Saturday, allowing investigators and railroad crews to better assess the damage then.  He says it did not appear any significant amounts of ethanol had spilled into a creek at the derailment site after staff from his agency checked downstream. Hessenius says a water sample from the creek hadn’t yet been lab tested, but said the water appeared uncontaminated after “a smell test.”

Earlier in the day, Friday, the National Transportation Safety Board said it was sending some of a 15-member investigative team from the site of a fatal train collision on the Mississippi coast to rural northwest Iowa, to look into a derailment that caused the ethanol-fueled fire. Some members of the team will be coming from Biloxi, Mississippi, where the agency is investigating a Tuesday crash in which a Texas tour bus was hit by a freight train at a crossing, killing four. Other members of the investigative team heading to Iowa  come from NTSB headquarters in Washington.