Khau Nguyen refused to use the propane heater in his rented Spokane Valley trailer Wednesday night.

That proved a deadly decision for Nguyen and his roommate, Phan Duong. The two died when a charcoal grill they were using for heat filled their trailer with carbon monoxide, then a smoky fire.

Authorities fear similar situations may happen in the next few days as thousands of shivering Inland Northwest residents struggle to find ways to heat homes still without electricity.

Carbon monoxide poisoning and house fires are a dangerous by-product of portable gas heaters and overused fireplaces, they said.

Seven other people throughout Spokane County had non-fatal cases of carbon monoxide poisoning late Wednesday or early Thursday, authorities reported. Symptoms of the condition - which can lead to brain damage or death - include nausea and dizziness.

No such injuries were reported in Kootenai County.

“If they’re using any type of heat, a wood stove, a kerosene heater, they’ve got to have ventilation,” said Chief Don Donart of the Kootenai County Fire Protection District. “These houses are so airtight that’s why they’re ending up gassing themselves.”

Nguyen and Duong passed out from the carbon monoxide and died of smoke inhalation just inside the front door about 11:30 p.m., Spokane Valley Fire District officials said.

“He was afraid of propane,” said Nancy Singleton, Nguyen’s landlord at the Greenacres Mobile Home Park. “He thought the tank leaked. He swore it was going to kill him.”

With the electricity out for the second straight night Wednesday and his electric furnace not functioning, Nguyen brought the grill inside the blue-and-white trailer, filled it with Kingsford briquettes and set them aflame.

Shortly thereafter, he and Duong were overcome by carbon monoxide gas spewing from the grill, fire officials said.

In their rush to get out, one of them kicked over the grill, sparking a fire that filled the trailer with smoke.

“They tried to get to the door, but didn’t make it,” said Assistant Chief Karl Bold.

The victims’ exact ages weren’t known late Thursday. Nguyen was in his 50s and worked as a printer, Singleton said. Duong, a woman in her late 30s, was a cook.

Four of the other carbon monoxide victims were rushed to Fairchild Air Force Base for treatment in the base hospital’s hyperbaric chamber, said Lt. Col. Robert Grant, chief of flight medicine.

Authorities said all the cases were caused by people without electricity trying to heat their homes with things like Coleman camp stoves and gas ovens - all of which give off the colorless, odorless carbon monoxide gas.

“Those things are designed to burn in the open so they need a lot of fresh air,” Kootenai County’s Donart said. If residents need to cook on their BBQs, do so only outside, he said.

Many people have burned logs in their fireplaces constantly since Tuesday. “Some of those fireplaces aren’t designed to take that kind of heat for that amount of time,” said Ken Gabriel of the Coeur d’Alene Fire Department.

In some cases heat is seeping through cracks in the masonry and igniting the insides of walls. A home on Victoria Drive in Coeur d’Alene caught fire Thursday morning after a wall near the fire stove got too hot and caught fire. No one was injured, Gabriel said.

Bold recommended that people burn intermittently through the day and let the fires die out at night.

Those with electricity also need to be careful as they try to heat their homes.

A fire, possibly caused by a space heater, badly damaged a house in Sandpoint Thursday afternoon. The fire was reported about 1 p.m. at the corner of Church and Washington streets. An elderly couple lived in the home but escaped the fire without injury.

In Post Falls, clothes and toys piled on an electric heater caught fire Thursday. Residents were able to put the blaze out before it caused much damage.

, DataTimes ILLUSTRATION: Color photo Graphic: The dangers of carbon monoxide

MEMO: Changed in Spokane edition.

The following fields overflowed: BYLINE = Adam Lynn Staff writer Staff writers Winda Benedetti and Kevin Keating contributed to this report.