Pacific (D), operates two drilling platforms on the Outer Continental Shelf (OCS). P employed Juan Valladolid as a general manual laborer--known in the trade as a roustabout. Juan spent about 98 percent of his time on one of D's offshore drilling platforms performing maintenance duties, such as picking up litter, emptying trashcans, washing decks, painting, maintaining equipment, and helping to load and unload the platform crane. Juan spent the remainder of his time working at Pacific's onshore processing facility, where he also performed maintenance duties, including painting, sandblasting, pulling weeds, cleaning drain culverts, and operating a forklift. While on duty at the onshore facility, Juan died in a forklift accident. P filed a claim for benefits under the LHWCA pursuant to the extension of that Act contained within the OCSLA. The OCSLA provides, in relevant part: 'With respect to disability or death of an employee resulting from any injury occurring as the result of operations conducted on the outer Continental Shelf for the purpose of exploring for, developing, removing, or transporting by pipeline the natural resources, or involving rights to the natural resources, of the subsoil and seabed of the outer Continental Shelf, compensation shall be payable under the provisions of the [LHWCA] ' 43 U.S.C. §1333(b). The Ninth Circuit reversed, held that the 'situs-of-injury' requirement, and a 'but for' causation requirement, was in appropriate and that 'the claimant must establish a substantial nexus between the injury and extractive operations on the shelf' to qualify for workers' compensation benefits under the OCSLA. The Supreme Court granted certiorari.