Legoland Korea Resort has initiated a recall for its unicorn hat after a Ministry of Trade, Industry and Energy (MOTIE) study found a hazardous substance that can cause deformed childbirth and erectile dysfunction.

According to Legoland, on Tuesday, a product safety inspection conducted by the Korean Agency for Technology and Standards, under MOTIE, found that the Chinese-made "Unicorn Hat (LL1-331)" contained nonylphenol, a hazardous substance. The agency said the hats contained 1.4 times more nonylphenol than the accepted limit.

Nonylphenols, a class of environmental hormones, are used in detergents, pesticides, and some plastics. Long-term exposure to nonylphenols can cause birth defects, sexual precocity, erectile dysfunction, and azoospermia.

According to LEGOLAND, the hat has been sold at Big Shop, its souvenir shop, since July 1, and a total of 292 caps were sold, 237 last year and 55 this year.

"We would like to express our sincere apologies to our guests at Legoland Korea Resort," the resort said in an announcement. "We immediately stopped selling the product, and we will take back all sold products and issue refunds."

Legoland stressed that if anyone who bought the hat brings the product to its customer center or store, or sends the product by courier by a cash on delivery method, it will provide a full refund regardless of whether the product was used or not.

"Please understand that we are taking measurements to retrieve the product, and the refund can only be issued once the product is returned," the amusement park said. "We apologize again for the inconvenience caused by the product, and we will work harder on quality control to prevent the same problem from happening again."