18939
Of the total 188 exposures , the mean age was 1 . 5 years ( range 6 months - 5 years ) and 60 . 6 % were male .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None