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: CONCLUSIONS : Our updated evaluation of diazinon provides additional evidence of an association with lung cancer risk .
### Output Text:
CONCLUSIONS : Our updated evaluation of <span class="chemical">diazinon</span> provides additional evidence of an association with lung cancer risk . 