Q: fuel injection service was done by a mechanic and I smell a chemical in my garage.

Hi there. Sounds like the mechanic used a chemical that includes washer cleaner that helps clean out the fuel injectors. This can burn, but it is very toxic. I recommend venting the garage while the fuel is being burned until you have to fill up the fuel tank. I recommend parking the vehicle outside until you need to get gas. The injection cleaner is not going to harm anything on the engine, but its harmful to people and pets. There was nothing spilled, it is just the chemical smell in the exhaust system after shutting off the engine. If you need further assistance with the smell that emits after a hot shut down, then seek out a professional, such as one from Your Mechanic, to help you.