They are safe. Most wormers come with a 14 day egg withdrawl recommendation, so if you worry about that, then toss the eggs for that long. Some people follow the recommendation, some ignore it. The risk is small, mostly that someone might have an allergic reaction to any medication residue that found it's way into the eggs. If the eggs are for your and your families personal use, then do what you are comfortable with as far as withdrawl, if you sell eggs, then I would not sell during the withdrawl period. I've used most of the common wormers at one time or another, some I use very regularly, I've never had an issue with any of them. If you know you have a worm issue, then that is what I would use.