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: This was a case of acute palsy of the recurrent laryngeal nerve and superimposed severe acute sensorimotor axonal polyneuropathy caused by high - dose disulfiram intoxication .
### Output Text:
This was a case of acute palsy of the recurrent laryngeal nerve and superimposed severe acute sensorimotor axonal polyneuropathy caused by high - dose <span class="chemical">disulfiram</span> intoxication . 