I can think of several reasons- noise, fumes, traffic, aesthetics, resale.

There are many chemicals used in both body shops and gas stations that are washed into the ground along with the things listed by Lil S. Many of those things contain heavy metals. If you are planning on growing food even in raised beds pass on this.

Since you're asking for realtor advice, the biggest advice I would give is re sale value. But just advice, I would agree with the other two posters. You will smell the fumes of paint, anytime they paint. Gas, anytime they get their tanks filled. We have several areas in my county that are now on the EPAs superfund site. Companies, (i wont name which ones) who illegally dumped in to the ground. After years of ground water movement, it affected all the wells of the nearby houses. While, it has been cleaned up, those homes are forever stigmatized. Most people dont want to live there, even though its been "cleaned up". Those homes also have lower resale values because of it.

The above three answers are right.

As a point of information, when you sell a gas station or auto body shop the buyer has to conduct specialized inspections (Phase I ESA) possibly a Phase II and potentially a Phase III depending upon the results of the Phase I assessment. These assessments and potentially the remediation of chemical waste in the soil are critical to a commercial transaction for the buyer.

If you are a buyer of a property close to any automotive type use, then you need to be extra careful with your property purchase as the risk of chemicals leaching into the surrounding areas is high.

Don't risk it. Especially with your intended use of planting food (or anything) into possibly contaminated soil. Even if the soil isn't contaminated right now, what is to stop the contamination from happening over time?

Edit: Yes, I'm a Realtor. And yes, the neighboring properties become stigmatized like HU-69721837 mentions above.