From Green Right Now Reports

An oil leak of still undetermined proportions in Colorado has soiled the South Platte River and forced employees of the Denver Metro Wastewater plant to wear masks protecting them from the benzene and VOC fumes emitting from the contaminated water.

Calgary-based Suncor acknowledged that the petroleum came from its refinery in Commerce City, and a spokesperson told Reuters on Wednesday that the leak had been stopped.

The clean up, however, continues. EPA officials have placed booms placed across the river as state and federal regulators continue to investigate try to find the leak’s precise origins. Some reports speculated that the oil had oozed from a broken pipeline spur connecting a main pipeline to the nearby Suncor refinery. But Suncor told Reuters that was not the case.

Environmentalists are concerned that a significant portion of the escaped oil may be deep in the river because Suncor mainly handles heavy tar sands oil, which can be more difficult to clean up.

“If the leak involves tar sands diluted bitumen, the contamination could be more severe,” said Natural Resources Defense Council spokesman Josh Mogerman said in a statement.

“Tar sands diluted bitumen spills are associated with significantly more submerged oil which cannot be contained by surface booms. Spill responders are still struggling to handle the submerged oil at Enbridge’s Kalamazoo oil spill. However, this spill shows the weakness in spill response and is yet another example of the very real risks inherent in tar sands infrastructure projects,” Mogerman said.

The spill was discovered on Sunday by a fisherman, Trevor Tanner, who noticed noxious fumes and a sheen on the water. His account, as reported by Mogerman:

I walked several hundred feet up Sand-Creek and there was an oil sheen the whole way and there was even a weird milky chocolaty sludge trapped in the small back-eddy below the confluence.  My fly smelled like gasoline.  My fingers smelled like gasoline.  I could see micro-currents and upwells in the water column that you usually just can’t see.  Something was terribly wrong.

Tanner called a hotline to report the leak, and the next day Suncor and EPA officials went into action.

Mogerman noted that the leak comes as some in Congress (several Republicans led by Sen. Richard Luger, R-Ind.) are trying to force the Obama Administration to quickly approve the Keystone XL pipeline that would carry billions of gallons of tar sands oil from Alberta, Canada to Houston-area refineries. (Read more about Lugar’s sudden interest in facilitating the pipeline, which does not run through Indiana, here.)

In November, President Obama called for a review of the Keystone pipeline plan in the wake of several citizen protests in Washington and a call for a possible re-routing by Nebraska elected officials concerned about the pipeline’s planned path through the ecologically sensitive Sand Hills region.

If the Keystone pipeline, operated by TransCanada, leaked in the Sand Hills region it could easily contaminate the Ogallala Aquifer, which supplies 80 percent of Nebraskans with drinking and irrigation water.

“At a time when companies like TransCanada and Enbridge are proposing to build tar sands infrastructure through our rivers and water resources—and are trying to speed up the process by skipping environmental review—this (Colorado) spill provides another sad example of what can go wrong with these projects,” Mogerman said.