@Iluviaporos - It won't be that bad, as the bees are pretty good at knowing how to protect themselves. They wouldn't carry dangerous materials into the hive and the country wouldn't let people sell it as a supplement if it could be that dangerous.
It still doesn't appeal all that much to me though.
Propolis has other benefits for bees. It's been shown in studies that they don't use it to block air. They use it to block out disease. And that means that if an animal, like say, a mouse, dies in the bottom of the hive and they can't move it, they will cover it in propolis to try and isolate it from the workers.
Makes you look at it in a different way, considering it's all gathered from the hive.