20-MC 20-Methylcholanthrene 3-MC 3-Methoxycholanthrene 3-Methylcholanthrene 56-49-5 Benz[j]aceanthrylene, 1,2-dihydro-3-methyl- Cholanthrene, 3-methyl- MC MCA Methylcholanthrene NSC21970 WLN: L E6 D6656 1A T&&&T&J R1