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: Severe rhabdomyolysis and acute renal failure secondary to concomitant use of simvastatin , amiodarone , and atazanavir .
### Output Text:
Severe rhabdomyolysis and acute renal failure secondary to concomitant use of <span class="chemical">simvastatin</span> , <span class="chemical">amiodarone</span> , and <span class="chemical">atazanavir</span> . 