A popular restaurant chain in China is offering refunds to more than 4,100 diners after two teens were caught on video urinating into a vat of hotpot broth in a private dining room at one of its locations.

Hotpots are vats brimming with boiling broth that customers fill with meat morsels, vegetables and other ingredients, then eat communally. Haidilao, with restaurants across China and in the U.S., U.K., Japan and elsewhere, specializes in this fare.

The pee-pranking patrons, 17-year-olds with the surnames Tang and Wu, were arrested after video of them went viral and sparked social media outrage. In the clip, filmed last month, a young man stood on a table at one of the company’s Shanghai restaurants, peeing into the roiling vat.

Haidilao came clean on Wednesday, saying they had not known about the incident until days later, after which it took time to locate the precise location of the restaurant.

While the broths are not served to other customers, it wasn’t clear whether the hotpot had been thoroughly cleaned and disinfected before the next customer partook, BBC News reported.

The company added that since such an act wasn’t on their bingo card, personnel had no playbook for such an incident.

“As management had never made contingency plans or given training for dealing with this type of incident, staff at our branch were unable to detect any abnormalities at the scene or uphold the safety of the dining environment,” the company said.

The peeing perps, who the BBC said were drunk at the time, were placed in “administrative detention” once police confirmed the identity of the teens. The chain also offered full refunds plus a cash lump sum equal to 10 times their bill to more than 4,100 customers who had ordered food between Feb. 24 and March 8.

“We fully understand that the distress caused to our customers by this incident cannot be fully compensated for by any means, but we will do our utmost to take responsibility,” the company said.