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: This study examined the utility of biometry for detecting alcohol - related fetal growth impairment .
### Output Text:
This study examined the utility of biometry for detecting <span class="chemical">alcohol</span> - related fetal growth impairment . 