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: Patient demographics , history of underlying drug or alcohol - related seizure disorder , estimated time from seizure to sample collection , history or suspicion of cocaine or amphetamine abuse , results of clinical urine testing for drugs of abuse , and assay results were recorded without patient identifiers .
### Output Text:
Patient demographics , history of underlying drug or <span class="chemical">alcohol</span> - related seizure disorder , estimated time from seizure to sample collection , history or suspicion of cocaine or amphetamine abuse , results of clinical urine testing for drugs of abuse , and assay results were recorded without patient identifiers . 