When you buy certain cotton products, you may notice a STANDARD 100 Oeko-tex certified label on them, like some of these weighted blankets. This certification proves that the cotton used to make the product has been thoroughly tested for harmful substances that may be leftover from the manufacturing process. The cotton is graded on a four-class system based on how much contact the product will have on the skin. If you see this label, you know that the fabric is safe to have consistent contact with the skin without any risk of adverse effects.