{'bhopal gas tragedy': [1, 0, 1, 3], 'methyl isocyanate': [1, 0, 2, 2], 'methyl isothiocyanate': [0, 0, 1, 0], 'ethyl isocyanate': [0, 0, 1, 0], 'gas': [9, 1, 9, 27], 'ethyl isothiocyanate': [0, 0, 1, 0]}