What kind of junk?
Heroin. But of course addicts will substitute other opiates when they are desperate. Perhaps I should not speculate on Tommy's drug habits, but he hung with a tough crowd. And, as I say bile duct cancer is highly correlated with substance abuse. Bile duct cancer (Cholangiocarcinoma) - Prevention
From Wikipedia:
Dee Dee:
Dee Dee struggled with drug addiction for much of his life, particularly heroin. He began using drugs as a teenager, and continued to use for the majority of his adult life. He appeared clean in the early 1990s but began using heroin again some time later. He died from a heroin overdose on June 5, 2002.[1]
According to other sources "Joey and Marky struggled with alcoholism."