After Jose died of lung cancer, his widow filed for benefits under the Black

Lung Benefits Act. To qualify for benefits under the Act, she had to show

the exposure to coal dust was a substantial contributing factor to his death.

Jose was a coal miner but also a longtime smoker. At the benefits hearing a

physician testified that coal dust was a substantial factor in his death. No

evidence was provided, however, The ALJ awarded benefits. On appeal,

should the court defer to the decision? What law applies?