as others may have said prague powder is dyed pink to make it obviously different from regular salt. In recommended quantities for curing meat (such as sausages, bacon, etc) it's perfectly fine. You just don't want to accidentally eat it by itself.
As for the debate on the health impact of nitrates/nitrites, keep this in mind--'uncured' products are labeled as uncured, even though they have the same amount of curing agents as 'pragued' products. The agents in uncured foods are just sourced from celery, which the FDA allows in it's packaging rules to be classified as uncured even though it's the same thing as prague powder.