A Fulton County warehouse operator agreed this week to clean up contaminated soil and surface water caused by a tenant who faces one of the largest environmental fines in recent Georgia history for polluting the Chattahoochee River.

American Sealcoat Manufacturing LLC, which has halted business at its factory near Six Flags Over Georgia, knowingly and repeatedly dumped a "black oily substance" into a tributary of the Chattahoochee, a judge ruled Aug. 13.

The company violated the Clean Water Act by discharging toxins and carcinogens in the stream bed without a permit. American Sealcoat was ordered to pay a $10 million fine.

The landlord, M&K Warehouses, will remediate the site under a settlement agreement with the Chattahoochee Riverkeeper reached this week. The riverkeeper credits M&K for working "diligently," and spending $500,000, to reverse the environmental damage caused by American Sealcoat.

"This case sends a clear message to other industrial operators and property owners that compliance with water quality laws is not optional, and hope that it encourages them to follow M&K's example of cooperation and compliance," Jason Ulseth, the riverkeeper, said in a statement.

Bob Norman, an attorney for M&K, said: “This was an unfortunate situation that M&K inherited from its tenant, American Sealcoat. … The company is glad to have all of this behind them.”