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: After verifying the epidural space , bupivacaine and triamcinolone diacetate were injected .
### Output Text:
After verifying the epidural space , <span class="chemical">bupivacaine</span> and <span class="chemical">triamcinolone diacetate</span> were injected . 