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: Chronic CBZ also decreased the incidence of seizure - related mortality in the cocaine - injected rats .
### Output Text:
Chronic <span class="chemical">CBZ</span> also decreased the incidence of seizure - related mortality in the <span class="chemical">cocaine</span> - injected rats . 