19417
Case report : A male worker in a chemical plant was accidentally exposed to the mixture of high - concentrated ethenone and crotonaldehyde for 5 min in an open space and worked continuously in the polluted area for approximately 12 h .
 Chemical: ethenone; Chemical: crotonaldehyde
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: ethenone, crotonaldehyde 
Answer:
 Chemical: ethenone; Chemical: crotonaldehyde