2719
Maternal exposure to PCBs and dioxins was found to be associated with an increased risk of wheeze and more frequent upper respiratory tract infections .
 Chemical: PCBs; Chemical: dioxins
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: PCBs; Chemical: dioxins