Several Oklahoma landowners are pressing FERC to investigate what they say amounts to collusion involving an environmental compliance monitor, a Cheniere Energy Inc. pipeline subsidiary and the agency’s own Office of Energy Projects (OEP).

Central Land Consulting LLC (CLC), which represents landowners on right-of-way for the Midcontinent Subheader Interstate Pipeline (Midship), said in recent filings with the Federal Energy Regulatory Commission the contractor appeared to show bias in favor of Midship in recent environmental reports. 

“Some notes appear to be direct statements from Midship while others have been sugarcoated” with serious details left out, CLC President of Operations Nate Laps said in a filing on Tuesday. The environmental compliance monitor, Dan Beisner,...