PAGE, Ariz. — Carbon monoxide poisoning killed one man and injured seven others Tuesday in a houseboat on Lake Powell.

Around 2:45 a.m., eight members of an Arizona family staying on a house boat in Rock Creek Bay on Lake Powell became ill and sent out a distress call, according to Glen Canyon National Recreation Area officials.

The 62-year-old man who first noticed the problem and began rousing members of his extended family suffered a heart attack and died during the evacuation. Seven people were flown by helicopter to a Page hospital; six have since been transported for treatment in a hyperbaric chamber in St. George.

The National Park Service is still investigating the incident, officials said.