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: The present study points to patient characteristics that may be of significance in the development of EPS due to haloperidol .
### Output Text:
The present study points to patient characteristics that may be of significance in the development of EPS due to <span class="chemical">haloperidol</span> . 