This page is to clarify how wool originating from a well known clothes manufacturer has been processed (We are not allowed to mention the companys name).
They state that all wool is more or less treated chemically in one way or another. The amount of chemicals that are needed in the manufacturing process depends on the quality of the wool.
They wool they use is of a very high quality, and therefore does not need a "strong" treatment. 
The wool has been lightly treated in chlorine to extract shells from the wool. Thereafter the wool passes through several cleansing baths to remove the chlorine entirely from the fabrics.
The company is then very careful that the leftover chlorine is processed through several processes that minimizes the enviromental risk.
Then the fabrics are coated with a thin layer of polyamid to prevent wool-fibres from sticking out again. The amount of polyamid are less than 1% than the wool-fibres and as such does not affect the wools natural benefits.
All in all their wool is treated, but done in a way that is eviromentally consious and thouroughly checcked. This is underlined by the by the fact that company has Eco-label and Wool mark-label.
Furthermore, the labels also ensures that theres is absolutely no use of azo-color material.