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: For specific groups of drugs , the risks were 1 . 56 ( 1 . 05 - 2 . 30 ) for aspirin , 1 . 03 ( 0 . 60 - 1 . 76 ) for pyrazolones , 0 . 80 ( 0 . 39 - 1 . 63 ) for paracetamol , and 0 . 94 ( 0 . 57 - 1 . 56 ) for nonaspirin NSAIDs .
### Output Text:
For specific groups of drugs , the risks were 1 . 56 ( 1 . 05 - 2 . 30 ) for <span class="chemical">aspirin</span> , 1 . 03 ( 0 . 60 - 1 . 76 ) for <span class="chemical">pyrazolones</span> , 0 . 80 ( 0 . 39 - 1 . 63 ) for <span class="chemical">paracetamol</span> , and 0 . 94 ( 0 . 57 - 1 . 56 ) for nonaspirin NSAIDs . 