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: RESULTS : We observed elevated lung cancer risks ( N = 283 ) among applicators with the greatest number of LT ( RR = 1 . 60 ; 95 % CI 1 . 11 to 2 . 31 ; Ptrend = 0 . 02 ) and IW days of diazinon use ( RR = 1 . 41 ; 95 % CI 0 . 98 to 2 . 04 ; Ptrend = 0 . 08 ) .
### Output Text:
RESULTS : We observed elevated lung cancer risks ( N = 283 ) among applicators with the greatest number of LT ( RR = 1 . 60 ; 95 % CI 1 . 11 to 2 . 31 ; Ptrend = 0 . 02 ) and IW days of <span class="chemical">diazinon</span> use ( RR = 1 . 41 ; 95 % CI 0 . 98 to 2 . 04 ; Ptrend = 0 . 08 ) . 