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: Contact with the skin can result in percutaneous absorption of the substance that inhibits aldehyde dehydrogenase and can induce acetaldehyde syndrome in case of alcohol use .
### Output Text:
Contact with the skin can result in percutaneous absorption of the substance that inhibits <span class="chemical">aldehyde</span> dehydrogenase and can induce <span class="chemical">acetaldehyde</span> syndrome in case of <span class="chemical">alcohol</span> use . 