26518
For the first time , alginate polymer has been applied to prevent dyes from leaching out of colorimetric oxygen indicator films , which enable people to notice the presence of oxygen in the package in an economic and simple manner .
 Chemical: oxygen; Chemical: oxygen
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: oxygen; Chemical: oxygen