A hard-hitting report by the 60 Minutes television news program sent shares of Lumber Liquidators, the retailer of hard-wood flooring, plunging on Monday by more than 20%.

The 60 Minutes report that aired Sunday presented evidence that Lumber Liquidators had sold laminate flooring made in China that contained formaldehyde levels that surpassed California health standards.

Lumber Liquidators had given investors a heads up as part of its recent earnings release that 60 Minutes was preparing to report negatively about the company, which caused the company’s shares to already fall by some 25% last week.

In a statement, Lumber Liquidators said the company complies with applicable regulations set by the California Air Resources Board and attacked  some of the evidence presented by 60 Minutes on Sunday. “These attacks are driven by a small group of short-selling investors who are working together for the sole purpose of making money by lowering our stock price,” the company said.

Lumber Liquidators is correctly pointing the finger at short-selling investors that bet against a company’s stock price, but that doesn’t necessarily weaken the evidence presented by 60 Minutes on Sunday evening.

Whitney Tilson, a hedge fund manager who has been betting against the shares of Lumber Liquidators since 2013, appeared on the 60 Minutes program, which describes Tilson getting a tip about the company’s China-made laminate flooring.

“Six months after he bet millions the stock would go down, Whitney Tilson got tipped off by someone familiar with Lumber Liquidators’ operations’ in China, who said he was missing the bigger story,” 60 Minutes reported on Sunday. Tilson said on the program that “the much bigger story, he said is that Lumber Liquidators was almost certainly purchasing formaldehyde-tainted laminated flooring in China.”

Not so long ago, Lumber Liquidators had one of the hottest stocks on Wall Street, reporting good-looking financial results that got Tilson’s attention. The stock closed over $119 in November 2013, just before Tilson launched his short campaign against the company. It has since become a battleground stock. The stock was halted for most of Monday morning, but was changing hands for $40 after trading began.