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: Haloperidol decreased the incidence of cocaine - induced seizures at the two highest doses , but the lowering of the mortality rate did not reach statistical significance at any dose .
### Output Text:
<span class="chemical">Haloperidol</span> decreased the incidence of <span class="chemical">cocaine</span> - induced seizures at the two highest doses , but the lowering of the mortality rate did not reach statistical significance at any dose . 