The electric bidet accessory for Toto's Z series caught fire in three separate incidents between March 2006 and March 2007, according to company spokeswoman Emi Tanaka.

"Fortunately, nobody was using the toilets when the fire broke out and there were no injuries," Tanaka said. "The fire would have been just under your buttocks."

The company will repair 180,000 toilet units manufactured between May 1996 and December 2001, she said. The faulty wiring is thought to have been caused by a manufacturing defect.

Toto has been a pioneer in fitting high-tech toilets with pressurized water sprayers -- a standard fixture in many homes.

The popular Z series features a pulsating massage spray, a power dryer, an in-bowl deodorizing filter, its Tornado Wash flush, and a lid that opens and closes automatically. Prices range from 200,500 yen to 310,500 yen.

The model is not sold overseas.