What worries me most is the cocktail effect. A little bit of chemical A is safe and a little bit of chemical B is safe but what about when you have both together. With the thousands of chemicals in use, it's impossible to test all the possible combinations. And then there is the 'organic' produce that isn't, imports from countries that don't follow the rules that our farmers do and so on.
Personally I do use pesticides but it's a last option when I practically don't have another way. I'm pretty sure anything I've grown is a lot safer than most of the veg in the supermarket.