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: Acute experimental models of renal damage to the proximal tubular , glomerular , and papillary regions of the rat were produced by administration of hexachloro - 1 : 3 - butadiene ( HCBD ) , puromycin aminonucleoside ( PAN ) , and 2 - bromoethylamine ( BEA ) , respectively .
### Output Text:
Acute experimental models of renal damage to the proximal tubular , glomerular , and papillary regions of the rat were produced by administration of <span class="chemical">hexachloro - 1 : 3 - butadiene</span> ( <span class="chemical">HCBD</span> ) , <span class="chemical">puromycin aminonucleoside</span> ( <span class="chemical">PAN</span> ) , and <span class="chemical">2 - bromoethylamine</span> ( <span class="chemical">BEA</span> ) , respectively . 