WASHINGTON (AP) — Oil services contractor Halliburton Inc. says it safely finished a cementing operation 20 hours before a Gulf of Mexico rig went up in flames. In testimony prepared for a congressional hearing Tuesday, Halliburton says it completed work on the well according to accepted industry practice and federal regulators.

Halliburton executive Tim Probert says a pressure test was conducted after the work was finished, and the well owner decided to continue. A copy of the testimony was obtained by The Associated Press.

The cause of the April 20 explosion is under investigation, but lawsuits filed after the disaster claim it was caused when Halliburton workers improperly capped the well — a process known as cementing. Halliburton denies wrongdoing.