OSAKA -- A sewage pipe ruptured in a restaurant in the Universal Studios Japan amusement park, prompting Osaka health officials to investigate, people familiar with the incident said Wednesday.

The pipe, roughly 10 cm in diameter, ruptured Monday evening in the ceiling of the basement of the Park Side Grill, a U.S.-style eatery run by USJ Co., operator of the film-theme park, they said.

Human waste flooded the floor to a depth of about 3 cm.