Grease star Jeff Conaway may have been plagued by drug and alcohol abuse throughout his life, but his issues with substance abuse had nothing to do with his death. At least, that's the opinion of the Los Angeles County Coroner. Last spring, the 60-year-old Taxi actor was found on unconscious in his Los Angeles home. Conaway, best known for his role as Kenickie, never woke up from a coma. While many initially assumed that the Celebrity Rehab patient had fallen back into old habits, that wasn't the case. According to the coroner, his death was accidental. TMZ is reporting that the list of causes includes: septic emboli (infected arterial blockage), aortic valve endocarditis (heart valve infection), coronary artery disease, pneumonia and encephalopathy (a brain disorder resulting from drug overdoses). Of course, whether or not these conditions were exacerbated by his ongoing drug use is another matter. A toxicology report was never performed because Conaway had spent weeks in the hospital, so nothing would have showed up in his blood.