Answer: To be absolutely certain of soil safety you'll probably want to send a sample to a soil testing lab. You can have them check for contaminates as well as pH, organic matter and fertility. Once your soil gets a clean bill of health, you can confidently raise vegetables. If there's confirmation of contamination, you can build raised beds and fill them with new topsoil for your veggie garden.
Your local Cooperative Extension office can recommend a local testing lab or two. Contact them at 805-934-6240.
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