Question: which type of refrigerant is the most harmful
[{'answer': 'Bromochlorofluorocarbon', 'provenance': [{'wikipedia_id': '592486', 'title': 'Refrigerant', 'start_paragraph_id': 8, 'start_character': 74, 'end_paragraph_id': 8, 'end_character': 97, 'bleu_score': 1.0, 'section': 'Section::::Environmental issues.\n'}]}, {'provenance': [{'wikipedia_id': '592486', 'title': 'Refrigerant', 'start_paragraph_id': 8, 'start_character': 0, 'end_paragraph_id': 8, 'end_character': 112, 'bleu_score': 0.8852140475440831, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10041677885703385004}, 'section': 'Section::::Environmental issues.\n'}]}]