The 42 inch, 1147-km, $4.2 billion Rover Interstate Gas Pipeline Project, the biggest natural gas pipeline under construction in the United States, has been set back indefinitely by environmental mishaps.

The release of 2 million gallons of drilling slurry near the Tuscarawas River in Ohio — as well as what Federal Energy Regulatory Commission officials term “several misstatements” about the developer’s work, has cast doubt on whether or not the pipeline will be completed according to schedule.

Rover begins in West Virginia and winds through Eastern Ohio and Western Pennsylvania before connecting with the existing Vector Pipeline in Michigan, the route the continues to dog the pipeline's development as it runs too close to camp sites, homes, and historical monuments like the Stoneham House.

Rover spokesperson Alexis Daniel said “we continue to actively work with FERC and the Ohio Environmental Protection Agency to resolve all issues in a manner that is satisfactory to all parties."

Barclays commodities analyst Nicholas Potter said Rover's exact date when service would start was a "moving target," saying "meaningful volumes" were not expected until 2018.