A new report from the Clean Label Project says some popular protein powders may actually be poisonous.

The report found “disturbing” levels of lead and cadmium in over-the-counter protein powers, with the highest amounts of the heavy metals being found in plant-based, organic and chocolate-flavored products.

According to the U.S. Environmental Protection Agency, there is no safe level of lead for human consumption and cadmium is a known carcinogen.

The heavy metals are known to cause complications to the heart, kidneys, gut, brain, respiratory and reproductive systems.

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The study tested 160 products from 70 of the top-selling brands – representing 83% of the market.

Nearly half of those products exceeded federal or state safety regulations. Of the products tested, the Clean Label Project said 47% exceeded California Proposition 65 safety thresholds for toxic metals.

The organization said two possible sources of the contaminants in protein powders are the contaminated soils where ingredients are grown and the packaging used for these products.

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