But three-judge 5th Circuit panel disagreed, saying the law includes congressional subcommittees, and reversed Engelhardt's ruling.
Prosecutors allege that Rainey during a May 4, 2010, congressional briefing failed to disclose information about the estimated rate that oil was spewing from BP's blown-out Macondo well after the April rig explosion. They also claim Rainey responded to a letter from a subcommittee chairman, then-Rep. Edward Markey, with false and misleading information about flow-rate estimates. Markey is now a Democratic senator from Massachusetts.
Rainey also faces a charge of making false statements. Also, after Engelhardt threw out the original obstruction charge, prosecutors obtained a new indictment on that charge. Rainey has pleaded not guilty. His defense lawyers declined comment Monday.
The 5th Circuit decision, dated Friday, clears the way a district court trial. A trial had been set for this past March, but Engelhardt postponed it, pending the outcome of the appeal.
The opinion by Judge Stephen Higginson for a panel that also included Emilio Garza and E. Grady Jolly said the text of the law in question is "plain and determinative" and that "all tools of statutory construction favor reading" the law to include subcommittees.
The explosion on the BP-operated drilling rig Deepwater Horizon killed 11 workers about 50 miles off the Louisiana coast and set off the nation's worst offshore oil disaster.