Thomas (plaintiff), a District of Columbia (District) resident, was employed by Washington Gas Light Co. (defendant) for work primarily in the District but also in Virginia and Maryland. In 1971, Thomas was injured while working in Virginia. He sought benefits under the Virginia Workmen’s Compensation Act (Virginia Act) and was awarded them by the Virginia Industrial Commission (Virginia Commission). In 1974, Thomas sought benefits for the same injury under the District’s workmen’s compensation law (District Act). The employer challenged his claim on the grounds that the Virginia Act precluded any other recovery and that the District owed full faith and credit to the Virginia decision. An administrative law judge held that the Virginia award was res judicata in the District to the extent that it would be res judicata in Virginia but that the Virginia Act did not preclude an award of additional benefits outside of Virginia. Thomas was then awarded benefits under the District Act, minus the amount he had received under the Virginia Act. The Benefits Review Board upheld the award. The Court of Appeals for the Fourth Circuit reversed. Thomas petitioned the United States Supreme Court for certiorari.