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Among the various environmental toxicants , polycyclic aromatic hydrocarbons ( PAHs ) are an important class of environmental pollutant , and many PAHs are known or suspected carcinogens .
 Chemical: polycyclic aromatic hydrocarbons; Chemical: PAHs; Chemical: PAHs
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: polycyclic aromatic hydrocarbons; Chemical: PAHs; Chemical: PAHs