The anniversary of the Deepwater Horizon rig explosion also marks a crucial deadline in the federal litigation spawned by the blast and the massive Gulf oil spill it triggered.

Wednesday is the deadline for filing claims to be included in a trial next year against rig owner Transocean Ltd. The February 2012 trial is designed to determine whether the company can limit what it pays claimants under maritime law and to assign percentages of fault to Transocean and other companies involved in the disaster.

Plaintiffs’ attorneys also are urging anyone with a potential claim to fill out a form by Wednesday to preserve their rights against other companies.

U.S. District Judge Carl Barbier in New Orleans is presiding over roughly 60,000 claims over the rig explosion and oil spill.