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: METHODS : We obtained fetal ultrasound measures from routine ultrasound examinations for 167 pregnant hazardous drinkers who were enrolled in a brief alcohol intervention study .
### Output Text:
METHODS : We obtained fetal ultrasound measures from routine ultrasound examinations for 167 pregnant hazardous drinkers who were enrolled in a brief <span class="chemical">alcohol</span> intervention study . 