(WBIR - KINGSTON) – The Environment Protection Agency (EPA) and Tennessee Valley Authority (TVA) announced they completed cleaning up the December 2008 coal ash spill at the Kingston Fossil Fuel plant.

Despite that completion, the company hired by TVA to clean up the spill is under federal investigation for a second time.

RELATED: TVA to pay Kingston coal ash spill victims $27.8M

Jacobs Engineering Group, Inc., workers filed three lawsuits against the company in the Sixth Circuit U.S. Court of Appeals because they claim the company lied about the danger of work cleaning up the spill.

FULL CASE: Greg Adkisson et al., v. Jacobs Engineering Group Inc.

Workers said the company did not warn or protect them from fly ash, which are the toxic, finer particles of coal ash.

This comes after Greg Adkisson, along with 48 other people, filed suit against Jacobs in the United States District Court for the Eastern District of Tennessee in August 2013. The suit also alleged Jacobs improperly protected them from toxic fly ash.

The suit alleged claims of outrageous conduct, battery, negligence, negligence per se, intentional and/or reckless failure to warn, reckless infliction of emotional distress, fraud, misrepresentation and fraudulent concealment, and strict liability for ultrahazardous or abnormally dangerous activity.

The Sixth Circuit U.S. Court of Appeals reversed Chief U.S. District Judge Thomas Varlan's previous decision to toss out three lawsuits involving the Jacobs Engineering Group Inc. workers and spouses without hearing any proof in the case.

PREVIOUS: VA Ash Spill measured in billions five years later

On Dec. 22, 2008, the wall of a huge storage pond broke at the Tennessee Valley Authority's Kingston Fossil Fuel power plant. The collapse of the earthen dike unleashed a tidal wave of more than one billion gallons of wet ash and sludge in Roane County, much of it falling directly into the Emory River and Clinch River.