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: Whereas cocaine - induced seizures were best characterized as brief , generalized , and tonic and resulted in death , those induced by BE were prolonged , often multiple and mixed in type , and rarely resulted in death .
### Output Text:
Whereas <span class="chemical">cocaine</span> - induced seizures were best characterized as brief , generalized , and tonic and resulted in death , those induced by <span class="chemical">BE</span> were prolonged , often multiple and mixed in type , and rarely resulted in death . 