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: These observations , in conjunction with clinical and laboratory evidence of extravascular hemolysis , are consistent with drug - induced hemolytic anemia , possibly involving both drug - adsorption and autoantibody formation mechanisms .
### Output Text:
These observations , in conjunction with clinical and laboratory evidence of extravascular hemolysis , are consistent with drug - induced hemolytic anemia , possibly involving both drug - adsorption and autoantibody formation mechanisms . 