The title of the article is ignorantly misleading, and the core paper is intentionally misleading. They very explicitly state that their grading is not based on dose or exposure, only on detection with a threshold of 1 ppm. The fun thing about positive/negative testing is that if you have a sensitive enough test you can find just about anything.
There's a good reason they're not naming-and-shaming: this study was performed by the "nonprofit arm" of the company "million marker." Their products include similar scattergun tests trying to take advantage of people, particulalry vulnerable couples experiencing fertility issues. Their website is full of pseudoscientific and tautalogical claims, implying health benefits while being careful not to promise anything: "The good news is that if you follow our recommendations and eliminate the sources of exposure, you can dramatically decrease your exposure levels." Their "services" also include elimination coaching: naming products to avoid undermines the core message of the study: "this problem is EVERYWHERE... and only we can help."