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: Children who have status epilepticus have continuous or rapidly repeating seizures that may be life - threatening and may cause life - long changes in brain and behavior .
### Output Text:
Children who have status epilepticus have continuous or rapidly repeating seizures that may be life - threatening and may cause life - long changes in brain and behavior . 