When BP's Texas City, Texas, oil refinery exploded in 2005, killing 15 workers and injuring hundreds, company officials came to know Brent Coon very well. Coon, who heads a Beaumont, Texas-based environment and personal injury practice, spearheaded the Texas civil litigation against BP following the accident, which the company eventually settled for more than $3 billion in damages. He now represents one of the survivors in last month's explosion of BP's Deepwater Horizon drilling rig in the Gulf of Mexico, which killed 11 workers and has led to the worst oil spill in U.S. history. And he's gearing up to…