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: Delirium was diagnosed in 14 ( 10 . 1 % incidence , or 1 . 48 cases / person - years of exposure ) ; 71 . 4 % of cases were moderate or severe .
### Output Text:
Delirium was diagnosed in 14 ( 10 . 1 % incidence , or 1 . 48 cases / person - years of exposure ) ; 71 . 4 % of cases were moderate or severe . 