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: Long - term use of any analgesic was associated with an overall odds ratio of 1 . 22 ( 95 % CI , 0 . 89 - 1 . 66 ) .
### Output Text:
Long - term use of any analgesic was associated with an overall odds ratio of 1 . 22 ( 95 % CI , 0 . 89 - 1 . 66 ) . 