UPDATE: The portion of the Riverwalk, from Scrappy Moore Field to the Boathouse, that was closed due to the fuel spill at Citico Creek has reopened. 

PREVIOUS STORY: Norfolk Southern has been identified as the source of the fuel spill that was discovered late Monday afternoon.

A spokesperson for the Chattanooga Fire Department says the spill originated from DeButts Yard and Norfolk Southern has taken responsibility for the spill and assured city, state and federal authorities on Monday afternoon that it is making every effort to minimize the impact on Citico Creek and the Tennessee River.

Norfolk Southern has hired several environmental remediation companies to do the cleanup work, which is expected to take several days.

The investigation into the cause of the spill will be handled jointly by the Environmental Protection Agency (EPA) and the Tennessee Department of Environment and Conservation (TDEC).

The spokesperson tells Channel 3, crews will be working around the clock to clean up the spill.

Stay with WRCBtv.com for updates to this story.

PREVIOUS STORY: Tennessee American Water has issued the following response to Monday's spill in Citico Creek:

"We responded immediately and feel confident that there is no threat to the drinking water supply. We were informed by emergency management personnel on Monday evening of a diesel spill on Citico Creek which is adjacent to our property.  We are monitoring the situation and have been in contact with TDEC. Emergency management personnel shared with us that an environmental cleanup company would be cleaning the spill. Our monitoring and analysis of water samples yesterday did not indicate any changes related to the spill.  We are also performing additional sampling while the cleanup continues. We have a plant operator on site 24/7 that monitors and samples at the plant at all times. Out of an abundance of caution, we are utilizing powdered activated carbon since yesterday evening.  The carbon is a protocol recommended by TDEC for emergency readiness. The carbon helps to eliminate any probable contaminants when the water is initially drawn into the plant from the river."

PREVIOUS STORY: Crews are taking booms into the water to help absorb the oil and prevent it from spreading.

Some of the oil has spilled into the Tennessee River.

According to CFD spokesperson, it is not currently known how long the cleanup process will take.  An investigation will take place once the cleanup is done. 

PREVIOUS STORY: Chattanooga Mayor Andy Berke is on scene accessing the situation at Citico Creek. 

Tennessee American Water is also accessing the situation. They are monitoring water for customers.

PREVIOUS STORY: The Chattanooga Fire Department is working to clean up a petroleum spill at Citico Creek. 

Monday night around 6:30 pm, the CFD was notified of the spill.  

Crews from the CFD, Chattanooga's Public Works Department and City Engineering are working with officials from the Environmental Protection Agency (EPA), Tennessee Department of Environment and Conservation (TDEC), the Coast Guard and HEPACO are working to clean up the river. They are also working on remediation and determining the material and its source.

According to Assistant Chief Danny Hague of the fire department's Special Operations Division, the amount of the material spilled is well in excess of 1,000 gallons.

Haz-mat crews with the fire department and Hamilton County Emergency Services deployed containment booms on the creek Monday night in an effort to contain the spill.

The CFD advises that the public may notice a sheen or odor on Citico Creek, or the Tennessee River south of where the creek enters the river. 

The public is asked to stay away from the site while crews work to clean up.

The Riverwalk is currently closed to vehicles and the public.

This is a developing story.