Thanks for the link, Kiwi. People need to understand the risks of taking some types of supplements. I think the keyword in that article is "contaminated". Another might be "excessive dosing" as in the use of Ephedra. Notice the names of the supplements quoted as problematic... fancy eye catching names.
You know where I live there was a radio show with a prominent medical internist on it, who recommended ephedra to just about everyone, even cardiac patients. A friend of mine came to me about her husband's doctor putting him on it. Her husband had had a heart attack. I in no uncertain terms explained the risks of that to her! So he did not in the end use ephedra. This was before the media coverage of the abuses of this drug/herb, too.

China has long sold contaminated products. They have added digoxin, Viagra, phenylbutazone and other drugs to their herbs for years. There are many articles on the net about this.
This is to pump up the response for the person using whatever it is, and to generate more sales.

Herbs in general should be used with extreme care. It took years for the drug interactions with St.John's Wort to become understood, and now we see warnings on medications to not use with St John's Wort, etc. Herbs are "little" drugs and can be very dangerous when used improperly or at all for certain patients. They can affect the liver and the metabolism of RX medications significantly.

People should research their products thoroughly before considering using them. A high price, or a slick website does not guarantee safety. Linus Pauling Institute, some other universities, and NIH and PubMed are good places to start when learning about a substance/supplement.

All supplement products should have exact labeling about what is in them and how much. The quality makers also include allergen listings. "free" of gluten, soy, lactose" is one example.
"made on equipment that processes nuts" is another. GMP is a US term that assures "good manufacturing practices" and USP may appear on labels.(but not all substances are in the USP) This means the content conforms to purity as spelled out in the US Pharmacopeia which is a chemical reference book that lists purity for many medically used substances.