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: By November 1984 the Committee on Safety of Medicines had received 82 reports of possible hepatotoxicity associated with the drug , including five deaths .
### Output Text:
By November 1984 the Committee on Safety of Medicines had received 82 reports of possible hepatotoxicity associated with the drug , including five deaths . 