A foul odor suspected of coming from a sewage line sickened at least 113 guests at two casinos, authorities said.

The guests, whose complaints included nausea, shortness of breath and scratchy throats, were released after hospital tests found no toxic substances in their blood, said Bob Leinbach of the Clark County Fire Department.The fumes apparently were sucked through the ventilation system into the Excalibur Hotel and Casino and the Tropicana Resort and Casino, a half-mile apart, Leinbach said. Guests began complaining of illness Sunday night.