4881
Using an embryo - larval bioassay , embryos were either treated with 1000 pptr ( parts - per - trillion , pg / mL ) 17 alpha - ethynylestradiol ( EE2 ) alone from 6h post fertilization ( hpf ) to 4 days post fertilization ( dpf ) , or pre - treated with dioxin ( 4 - 5 hpf ) prior to EE2 .
 Chemical: 17 alpha - ethynylestradiol; Chemical: EE2; Chemical: EE2
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: 17 alpha - ethynylestradiol; Chemical: EE2; Chemical: EE2