They’re completely safe what comes to Potassium-40 radioactivity! You need to eat a massive amount of them to even reach the point where you experience radiation sickness. Actually, you might experience excessive potassium toxicity levels first. (Or you might not! Human bodies are equipped to get rid of excess potassium.) Or, you know, you might experience the problems of stuffing too much stuff down your gullet. There’s only so much stuff you can fit in your stomach at one time.