Answer: You are prudent in thinking about chemical residue on the grass clippings. As a general rule it is a good idea not to use clippings from a lawn recently treated with herbicides or pesticides or other chemicals on any garden, but especially your vegetable garden. After several mowings some gardeners feel comfortable using them to mulch around ornamental plants such as shrubs, especially after composting. For a definitive answer, though, you can contact the product manufacturer.
Fertilizer alone should not present undue risk, although some gardeners use only organic fertilizers rather than synthetic as a matter of personal preference.
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