MINNEAPOLIS (WCCO) — When it comes to boats and danger, you may think of drowning or crashing. But there’s another danger, a silent one.

READ MORE: Enjoying The Weather Extremes Of Como Park Zoo & Conservatory

David Schuester and his young daughter, Sierra, live on Eagle Lake in Maple Grove. Sierra ended up in the hospital after being poisoned by carbon monoxide in an open air boat.

Sierra is all smiles now. But two weeks ago, Sierra was sitting in a hyperbaric chamber instead of walking in the sun.

The July 4 injury she incurred was an invisible one.

“For about 5 minutes, she was sitting right here on the swim platform,” her father said.

And that’s when it happened.

“She just started crying, and she wasn’t responsive,” Schuester said.

After a 45 minute ride on a tube and a few minutes on the back of the boat, she had inhaled enough carbon monoxide to poison her.

READ MORE: Does Cold Weather Affect COVID Test Kits And Results?

Schuester says a neighbor had been through the same thing, so they knew what to do and took her to the hospital.

“She had to spend two-and-a-half hours at two-and-a-half atmospheres of pressure,” Shuester said.

Sierra is not alone.

The DNR says even in open air, anyone above or behind a motor can be at risk.

“People need to remember, you know, that carbon monoxide is an issue. So if the motor is on, don’t sit on the back of your boat, don’t pull somebody on the back of your boat within 20 feet on your boat,” said Kara Owens, a DNR boating and water safety specialist.

Dr. Cheryl Adkinson, who specializes in emergency medicine, suggested being even more cautious. She suggests staying 60 feet back.

“It can be fatal at the scene, it can be life threatening, it can cause serious consequences down the line,” she said.

MORE NEWS: 'I Was Flabbergasted': Missing Badge Of Hastings Officer Killed In 1894 Rediscovered

There are a few things you can do prevent exposure. You can put a detector on the rear of your boat. There’s also a device called a fresh air exhaust that claims to knock out 90 percent of the fumes.

Susan-Elizabeth Littlefield