A ventilation pipe on the water heater was found to have come off, apparently when the device was moved recently.
The teens were responding well to treatment at Intermountain Medical Center in Murray and were expected to fully recover.
Carbon monoxide safety tips
CO alarms should be installed in a central location outside each sleeping area and on every level of the home and in other locations where required by applicable laws, codes or standards. For the best protection, interconnect all CO alarms throughout the home. When one sounds, they all sound.
Follow the manufacturer's instructions for placement and mounting height.
Choose a CO alarm that has the label of a recognized testing laboratory.
Call your local fire department's non-emergency number to find out what number to call if the CO alarm sounds.
Test CO alarms at least once a month; replace them according to the manufacturer's instructions.
If the audible trouble signal sounds, check for low batteries. If the battery is low, replace it. If it still sounds, call the fire department.
If the CO alarm sounds, immediately move to a fresh air location outdoors or by an open window or door. Make sure everyone inside the home is accounted for. Call for help from a fresh air location and stay there until emergency personnel arrive.
If you need to warm a vehicle, remove it from the garage immediately after starting it. Do not run a vehicle or other fueled engine or motor indoors, even if garage doors are open. Make sure the exhaust pipe of a running vehicle is not covered with snow.
During and after a snowstorm, make sure vents for the dryer, furnace, stove and fireplace are clear of snow build-up.
A generator should be used in a well-ventilated location outdoors away from windows, doors and vent openings.
Gas or charcoal grills can produce CO only use outside.
Source: West Valley City Fire Department