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: Tubular damage produced by HCBD or BEA was discriminated both quantitatively and qualitatively from glomerular damage produced by PAN .
### Output Text:
Tubular damage produced by <span class="chemical">HCBD</span> or <span class="chemical">BEA</span> was discriminated both quantitatively and qualitatively from glomerular damage produced by <span class="chemical">PAN</span> . 