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: However , our findings for both liver cancer and follicular cell lymphoma warrant follow - up to better differentiate effects of metolachlor use from other factors .
### Output Text:
However , our findings for both liver cancer and follicular cell lymphoma warrant follow - up to better differentiate effects of <span class="chemical">metolachlor</span> use from other factors . 