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: In contrast , haloperidol demonstrated an ability to reduce cocaine - induced seizures without significantly reducing mortality .
### Output Text:
In contrast , <span class="chemical">haloperidol</span> demonstrated an ability to reduce <span class="chemical">cocaine</span> - induced seizures without significantly reducing mortality . 