Round one tests results, conducted by the Department of Environmental Quality, are so far inconclusive as to what the substance is. Authorities believe it is some type of petroleum product containing diesel, according to OCEM Director Tim Craighton.

The source is thought to be somewhere near Beggs or south of Beggs, flowing toward Okmulgee. They were putting kayaks into the water Saturday to try to track it down. A HAZMAT team also is using booms to stop the substance from spreading.

The Oklahoma Corporation Commission says it doesn't believe the substance is crude oil.

Craighton says someone noticed "something" in the Deep Fork River near Schulter on Thursday.

DEQ tests now confirm that something is a petroleum product with diesel in it that's mucking up the river for about 10 miles between Okmulgee and Macintosh counties.

A contractor is now putting booms in the river to help absorb the substance and stop it from seeping into Eufaula Lake.

"It is a concern," Craighton said. "We do know right now that it has not reached Eufaula Lake. We will be stopping it before it gets to Eufaula Lake."The EPA is investigating where the spill originated.

Craighton says residents of Okfuskee County reported seeing a black substance in their water on Sept. 1. If this is a related matter, it would mean it has traveled 80 miles in the water.

If you've seen the substance in the river on an earlier date, you're asked to call Okmulgee County Emergency Management at 918-759-9984.

The current spill is not believed to be any immediate danger to the public, authorities say.