An appeals court has let a long-simmering lawsuit against the Basel Action Network go forward.

In a decision reached on June 29, the U.S. Seventh Circuit Court of Appeals in Chicago affirmed an earlier ruling in granting Intercon Solutions the right to have its defamation case against the watchdog group heard by a state court. BAN had been hoping to have that ruling overturned based on an anti-SLAPP law in Washington, where the group is based, but appeals judges cited a recent case there that found the statute unconstitutional and therefore “unenforceable” under Illinois law.

Anti-SLAPP laws are intended to protect parties from defamation lawsuits brought forth “not to prevail, but to impose on the speaker the costs of defense, which can be substantial,” the ruling explains.

While Illinois has its own anti-SLAPP law in place, BAN’s legal team chose to invoke Washington’s statute in the appeals court to challenge Intercon’s case, which alleges the group knowingly made false statements to the media, public and its competitors in denying the firm’s certification in 2011.

According to BAN, Intercon was found to be illegally exporting hazardous waste, including CRT devices, to Hong Kong. The company has denied those allegations.

BAN’s executive director Jim Puckett said in a statement the suit was “designed to harass BAN in order to make us fearful of telling the truth about unscrupulous industry behavior.”

“Now that the law we based our appeal upon has been repealed, we look forward to presenting our evidence to a court of law and defending ourselves and our First Amendment rights to tell the truth,” Puckett said.

Intercon did not return a request for comment.

The case will now head back to its originating state court, the Eastern Division of the Northern District of Illinois, where the trial will be heard by judge Virginia Kendall.