22059
A total of 463 vanadium - exposed workers ( exposed group ) and 251 non - exposed workers ( control group ) were recruited from a Steel and Iron Group in Sichuan , China .
 Chemical: vanadium; Chemical: Iron
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: vanadium; Chemical: Iron