Bally’s in Atlantic City reportedly failed to inform its visitors about water that may have been tainted with lead for seven months.

Though the casino hotel knew about the test results in September, it took until March 4 to warn guests, the New York Post reports. A spokesperson for its parent company Caesars Entertainment (CZR), which is currently in Chapter 11, told the news site, “We did not handle this information appropriately” and “We take full responsibility for our failure to act promptly last fall.”

The tests were conducted on Aug. 27 by an independent lab, according to the Post. Results showed that the hotel had lead levels of 17.8 micrograms per liter, passing the acceptable 15 microgram threshold. There were dangerous levels of lead in seven out of the 20 sites that were tested, the highest of which was found in the janitor’s closet, measuring at 1,300 micrograms per liter. Deputy executive director for the Atlantic City Municipal Utilities Authority, which provides the city with drinking water, told the Post that he hadn’t seen levels that high in 15 years.

Bally’s received the test results in September and sent them to the New Jersey Department of Environmental Protection, the Post reports. Though the DEP got them the following month, it didn’t act until February when it sent the casino a letter of non-compliance. Bally’s then closed down the seven sites on March 4 and posted warnings for guests, and then proceeded to retest the water.

The spokesperson told the Post that retests found that all 20 locations either had acceptable or undetectable levels of lead, so they concluded that “either the initial samples were corrupted or the initial testing procedures were flawed.”

A Caesars spokesperson told Fortune that the company takes “strong exception to the main conclusion of the Post story.” Since there is only one source of water for the building and no lead pipes, he said, it was unusual for only seven out of 20 sources to have been affected. He added that it’s “reasonable to conclude” those first tests were incorrect, and it’s very unlikely any guests were exposed to dangerous levels of lead at any point. However the spokesperson did acknowledge, “that in no way excuses us from having not acted when the initial test results became available.”