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: Despite increasing reports on nonionic contrast media - induced nephropathy ( CIN ) in hospitalized adult patients during cardiac procedures , the studies in pediatrics are limited , with even less focus on possible predisposing factors and preventive measures for patients undergoing cardiac angiography .
### Output Text:
Despite increasing reports on nonionic <span class="chemical">contrast media</span> - induced nephropathy ( CIN ) in hospitalized adult patients during cardiac procedures , the studies in pediatrics are limited , with even less focus on possible predisposing factors and preventive measures for patients undergoing cardiac angiography . 