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: Treatment duration longer than 1 year was associated with an eightfold increased risk ( OR = 7 . 7 , 95 % CI 0 . 9 to 69 ) .
### Output Text:
Treatment duration longer than 1 year was associated with an eightfold increased risk ( OR = 7 . 7 , 95 % CI 0 . 9 to 69 ) . 