An investigation by the Interior Department’s Office of Inspector General (OIG) revealed that Royal Dutch Shell benefited during the awarding of oil shale leases by the Bureau of Land Management (BLM) in 2005-2006, but it did not find any evidence that the producer committed any criminal violations, according to a new report by the OIG.

The OIG initiated the investigation based on allegations that Shell received “insider information,” among other irregularities, during the BLM awarding of leases to research, develop and demonstrate (RDD) oil shale in 2005 and 2006. The investigation was expanded to include former Interior Secretary Gale Norton, who went to work for Shell after leaving the federal government.

“We found that Norton was very interested in the RDD program during her tenure as secretary, but we did not find evidence to conclusively determine that Norton violated conflict of interest laws, either pre- or post-employment with Shell,” wrote Acting OIG Mary L. Kendall in a memo that accompanied the report to Interior Secretary Ken Salazar.

However, “we discovered that BLM appeared to give preferential treatment to Shell in two specific [areas] regarding these leases. We found that two of Shell’s bid proposals included acreage amounts in excess of the allowable amount specified in the Federal Register notice, and that someone in BLM changed the amount to comply with the requirements.

“BLM did not disqualify Shell’s bids. We also found that Shell submitted three bids, while other prospective bidders were allowed to submit only one bid. Shell was awarded leases on all three bids. No other company received more than one,” said Kendall.

The OIG said it presented the results of its investigation to the Department of Justice, which has declined to proceed with criminal prosecution.