Heavy metals are naturally occurring, but whether protein powders contain harmful substances, I would not trust the clean label project. Much of their information has been proven to be inaccurate. They came under scrutiny when they tried to sue champion pet foods based on information they had published about high levels of lead and other contaminants that they supposedly found in the food. However, the food was tested for the lawsuit, and the lawsuit was found to be baseless. The information that the clean label project had was incorrect. I have also compared their results to consumer lab, and based on that, some of their stuff for supplements and things is not correct. I honestly think they may be making up some of this information. How do you know that they actually tested? Because they tell you? Anyone can make a website and put whatever values on it they want. I would take consumer lab has a much more trusted source of information. Also, many companies of protein powders in supplements will give you a certificate of analysis because they test their own food because they don’t want to be on the line if something happened. So you could ask them, how do you test your food? How do you make sure that contamination doesn’t occur throughout your production line? Could you provide me test results? You really should look up this lawsuit with champion pet foods. This brand is probably one of the least contaminated on the market, and a clean label project was saying that this food had contaminants, but if you look at other foods on there like Science Diet, those apparently pass. I don’t think that clean label project actually file the lawsuit. I think that it was filed by a third-party based on the results that were obtained from clean label project and the lawsuit was thrown out when those results turned out not to be accurate.