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: Rats died from cardiac hypertrophy with severe acute and chronic congestion of the lungs , liver , and other organs .
### Output Text:
Rats died from cardiac hypertrophy with severe acute and chronic congestion of the lungs , liver , and other organs . 