An ExxonMobile underground pipeline ruptured in a Mayflower, Arkansas subdivision on Friday, forcing the evacuation of 40 homes.

Mayflower Police Chief Robert Satkowski said that the evacuations will remain in effect over-night. The chief also stated that it's too early to say how much oil spilled, but crews have prevented it from getting into Lake Conway. That was a big concern all day; the work ahead will focus on clean-up around the affected areas in town.

KATV News:

Chief of Police Bob Satkowski. He confirmed to Channel 7 News that the Northwoods subdivision on Highway 89 was evacuated because of health risks from the crude oil fumes and possible fires should any sparks reach the oil. Faulkner County Judge Alan Dodson said in a LIVE interview on Channel 7 News at 6:00 that the oil flowed into the storm drain system, a drainage ditch, under Highway 365 and under Interstate 40. Emergency responders managed to stop the flow at all locations. They are now working to strengthen the earthen dams they have set up to ensure the oil does not begin moving again. Once that is done, they will create an underflow culvert that will allow water to drain through without releasing the oil into Lake Conway and then they will begin the cleanup process. A Hazmat team from the Office of Emergency Management is on site. They said that a lot of residual oil flowed down Starlight Road - one of two main streets in the subdivision.

The spill prompted evacuations as clean-up crews tackled some drainage areas in town where the oil flowed to. Along Highway 89 across from Lake Conway, crews sealed off two pipes under the road to keep oil from flowing from a city drainage pond into the lake.

An apparent breach in the Pegasus pipeline occurred late Friday afternoon. The pipeline has been shut off and crews are working to contain the spill.

Exxon Mobil said it's investigating the cause and working with local authorities in clean-up efforts. The company added that the breach was in a pipeline that originates in Illinois and carries tar sands oil to the Texas Gulf Coast.

In 2009, Exxon modified the capacity of the Pegasus pipeline, increasing the capacity to transport Canadian tar sands oil by 50 percent, or about 30,000 barrels per day. In a 2012 report, Bloomberg News reported the pipeline daily capacity to be 96,000 barrels of oil per day.

Tar sands oil is the most toxic fossil fuel on the planet, that leaves in its wake scarred landscapes, a web of pipelines, and polluting refineries.

Operational enhancements, such as new leak detection technology, were also reported to be "incorporated to support ExxonMobil Pipeline Company’s primary focus on operating its pipelines in a safe and environmentally responsible manner."

"The expansion of the Pegasus Pipeline is another example of how ExxonMobil Pipeline Company is continuing to develop new projects that provide valued services and enhance supply security," said Gary Pruessing, president, ExxonMobil Pipeline Company.

The Pegasus Pipeline was down for a week of maintenance in mid-December of 2012, possibly a starting point for determining what caused Friday's spill.