The state Environmental Protection Department says the company tested the generators on May 26 and Aug. 18 at all 68 of its New Jersey stores. The agency says the tests were run remotely from the company's Atlanta headquarters.
State rules prohibit the use of generators when air quality is poor.
Home Depot may appeal the fine.
A company spokeswoman says she couldn't comment specifically until she learns more details of the alleged wrongdoing.
Information from: Asbury Park Press, http://www.app.com