Nathan Bomey

USA TODAY

Certain types of laminate flooring made by Lumber Liquidators (LL) have a greater risk of causing cancer or other health problems than previously believed, U.S. health regulators said Monday.

The Centers for Disease Control and Prevention said Monday that people who purchased the China-made flooring are about three times more likely to get cancer than it had calculated earlier this month — a revelation that rattled investors, who sent Lumber Liquidators stock down 19.8% to close at $11.40.

The CDC had said on Feb. 10 that formaldehyde levels in select versions of the company's laminate flooring could cause two to nine cancer cases per 100,000 people. The new estimate is six to 30 cases per 100,000 people, the CDC said Monday.

Lumber Liquidators sells more than $120 million annually in laminate flooring, including products from the U.S. and Europe, according to a quarterly filing with the U.S. Securities and Exchange Commission. Last year, it suspended sales of China-made laminates after accusations of carcinogenic qualities surfaced.

Tessy Contreras, a homemaker from Texas City, Tex., and her husband Gilberto installed Lumber Liquidators laminate flooring affected by the issue in their home two to three years ago. She said Monday's revelation was scary because she has 6-year-old and 15-year-old sons in the house. She had completed air-quality tests with Lumber Liquidators last year after the concerns first emerged.

Controversy chops into Lumber Liquidators' sales

The discrepancy in the CDC's calculation stems from regulators initially using an incorrect figure for ceiling height to determine exposure risk.

In addition to cancer, people exposed to the flooring are also susceptible to increased risks of exacerbated respiratory issues such as asthma and eye, nose and throat irritation, the CDC said.

The agency said its recommendations would probably not change: "We strongly stress taking steps to reduce exposures, which should alleviate respiratory and eye, nose and throat irritation. These steps should also reduce the cancer risk."

Lumber Liquidators said in a statement that the CDC's "revised calculation overestimates any potential health risks from these products, and we are encouraged that CDC is seeking a broader review of their conclusions."

The CDC's website has information on how to reduce exposure to formaldehyde, as well as some specific details for people who bought flooring from Lumber Liquidators.

The U.S. Environmental Protection Agency says that to reduce exposure to formaldehyde in general, people should improve ventilation, use dehumidifiers and clear the collection tray regularly, as well as use air conditioners to maintain a moderate temperature.

The issue with Lumber Liquidators came to the public's attention in March 2015 when the CBS News program "60 Minutes" aired an investigation into the China-made products.

Lumber Liquidators sentenced in wood import scheme

Soon thereafter, the company's sales hit a rough patch in the third quarter and the CEO resigned. The company halted sales of China-made laminate flooring in March 2015 after the "60 Minutes" report and offered customers free air-quality tests.

Investors are fretting that renewed concerns about the company's products will dent the bottom line. The company's net sales in the third quarter of 2015 — the last stretch in which numbers have been reported — fell 11.3% to $236.1 million, compared to the third quarter of 2014.

Laminate flooring represented 13.2% of net sales in the third quarter, down from 18.5% a year earlier.

Contreras, of Texas City, Tex., said she is considering paying for her own air-quality tests because she's not sure whether she can trust Lumber Liquidators.

"I went to the store and said, 'What responsibility are you taking? Ya’ll should come out and pull this wood up and replace it, no charge,'" Contreras said, recalling her reaction last year.

Lumber Liquidators said in a statement that it remains "committed to operating with integrity and delivering quality flooring to our customers."

In an unrelated matter, Lumber Liquidators recently agreed to a criminal settlement involving $13 million in penalties and five years of probation after acknowledging it was guilty of illegally importing wood from forests that are home to endangered species.

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.