In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: The role of p - aminophenol in acetaminophen - induced nephrotoxicity : effect of bis ( p - nitrophenyl ) phosphate on acetaminophen and p - aminophenol nephrotoxicity and metabolism in Fischer 344 rats .
### Output Text:
The role of <span class="chemical">p - aminophenol</span> in <span class="chemical">acetaminophen</span> - induced nephrotoxicity : effect of <span class="chemical">bis ( p - nitrophenyl ) phosphate</span> on <span class="chemical">acetaminophen</span> and <span class="chemical">p - aminophenol</span> nephrotoxicity and metabolism in Fischer 344 rats . 