The Waterloo Fire Department responded at about 9:30 a.m. Thursday to a carbon dioxide alarm sounding at McDonald’s, located at 176 Marketplace Drive.

The fire department cleared the scene by 9:45 p.m. and said McDonald’s would be closed until its vendor could inspect the alarm and system. A leak was discovered on a carbon dioxide tank inside the business.

The fast food restaurant was back open as of early Thursday afternoon with some menu offerings limited.