One of the deadliest dangers in boating is carbon-monoxide poisoning. Last July, a 7-year-old Flagstaff girl died from carbon-monoxide poisoning during a boating trip at Lake Powell.

Carbon monoxide is an odorless, tasteless gas that in sufficient concentrations can replace the oxygen in your lungs, which can be fatal.

Carbon monoxide is produced not only by boat engines but also by generators, making it a special concern with houseboats. Houseboats rented at Lake Powell marinas have carbon-monoxide detectors. But privately owned houseboats may not have them.

Here are safety tips from the National Park Service and the U.S. Coast Guard:

• Do not allow passengers to congregate around engines or the backs of boats when engines or generators are running. This is especially important if the boat is enclosed for warmth.

• Maintain fresh-air circulation throughout the boat at all times. Run exhaust blowers whenever the generator is operating.

• Some boats vent carbon monoxide out the back, and the deadly gas can collect under the swim step and other spaces under the boat. The gas remains there long after engines and generators have been shut down. Don’t play or swim under the swim step or under the boat.

• Although carbon monoxide can be present without the smell of exhaust fumes, if you smell exhaust fumes, carbon monoxide also is present. Take immediate action to dissipate these fumes.

• Treat symptoms of seasickness as possible carbon-monoxide poisoning. Get the person into fresh air immediately. Seek medical attention if you can’t rule out carbon monoxide.