Shatnez - Prohibited Types of Fabrics

Dear inquirer, It is very difficult to determine whether a garment contains shatnez solely by reading its label (though it is still necessary to read it, as sometimes it clearly states wool and linen, which is forbidden); this is because, according to the law, manufacturers are not required to list materials that make up less than 2% of the garment (and some places even do not require listing for amounts up to 5%). From the perspective of halacha, the garment is forbidden even if there is a single thread that causes shatnez. Therefore, the only option is to have the garments tested in a specialized shatnez laboratory. After multiple tests of different garments, one can begin to discern what might be problematic and what is not (depending on the country of origin and the types of garments). If you find someone who is experienced in the field of shatnez and is familiar with the types of garments you mention, and from their experience assures you that they contain no shatnez, it may be possible to rely on their expertise. You can verify this even by making a phone call to a shatnez laboratory. I will include here some phone numbers: 

1) 1-599-500-667 

2) 570-6906 (03). 

In my opinion, what usually raises the most concern is when the label states that the garment contains wool, linen, blended fibers, or recycled fibers. 

With blessings, Rabbi Nachum