While humans eat plenty of soy, they don’t eat the bean’s roots, where the leghemoglobin is found. Leghemoglobin is structurally similar to proteins that we consume all the time, and Impossible says it’s had experts confirm its meatless meat is safe. After the company asked the FDA for an independent review, the agency didn’t deem leghemoglobin unsafe, but it also didn’t recognize it as safe. (Impossible can still sell the burger, and plans to re-petition the FDA.)