In 2008, during the coldest winter in decades, a Utah family faced a "perfect storm."
Snow was piling up on the roof of their manufactured home, their tiny infant was sickly and church members were buzzing about the possibility of child abuse.
By spring, the couple -- Mary and David Conrad, who as practicing vegans ate no meat products -- were charged by state welfare authorities with the nutritional and medical neglect of their baby Daniel.
"When you saw this child, he looked like he was on death's door, he was so green," said Clint Greenhalgh, 46, and a neighbor in the couple's low-income town of Manti.
But the Conrads were quickly convinced by a scientist friend, Thomas L Rodgers, that something else was sickening Daniel.
They blamed a precarious set of events -- cold weather, unrelenting snow and government regulations that allow the furnace vents in their manufactured home to be placed only three feet apart.
They say Daniel, now a healthy 16-month-old, was poisoned by carbon monoxide, also known as "the silent killer," which they believe was sucked into their house through a fresh-air vent.
For the next eight months, the Conrads, who have four other children age 6 to 16, waged a successful battle against Utah's Division of Child and Family Services and the courts to keep Daniel.
Warning Others About Carbon Monoxide
Today, they are warning other families of the dangers of low-level carbon monoxide poisoning, especially in factory-built homes.
"Mobile homes have stubby little vents and the snow cover adds to the risk," said Thomas Greiner, associate professor of engineering at Iowa State University. "You get cold weather and a potential for snow buildup that blocks the intake and exhaust."
"I have seen it happen in other types of furnaces and with short vents on flat roofs," he told ABCNews.com. "In several cases we had people almost die. One went to the hospital three times with undiagnosed problems."
There will never be conclusive proof that Daniel was poisoned by lethal exhaust fumes, but his curious case illustrates the difficulty in deciding when to test for carbon monoxide poisoning, which brings between 15,000 and 40,000 Americans a year into emergency rooms, according to the Centers for Disease Control and Prevention.
In the Conrads' case, the problem was visible, according to one witness, former state senator and heating specialist Parley Hellewell.
"When it was cold, you could see the exhaust come out of one [vent] and go down the other," he told ABCNews.com.
Hellewell and Rodgers had intervened in a similar Utah case in 2005. A family was charged with child abuse when one baby died and another appeared malnourished. The family was vindicated when experts found the furnace exhaust and an old air vent were only 11 inches apart, causing carbon monoxide to poison the entire family.
"It's definitely a hidden hazard and something needs to be done about it," he told ABCNews.com.
The Conrads' story has caught the attention of local media, state legislators, the Sierra Club and now, the Department of Housing and Urban Development, which regulates the design of manufactured homes.
The family wants local and state codes -- which require the vents to be at least 10 feet apart, much stricter than HUD's code -- to be enforced in manufactured homes. And, because Daniel was never tested, they want to require hospitals to routinely administer a simple blood test to detect carbon monoxide poisoning.
Carbon Monoxide Dangers
"Any idiot can see [the ventilation] is foolhardy and dangerous," said David Conrad. "Calling it safe violates any code in the whole country and I say it's insane."
In Conrad's case, the stubby vents were located on the north-facing, shady side of the roof where snow is protected from the sun and "inclined to pile up."
Blocking a combustion air supply return diminishes oxygen to the combustion chamber of the furnace and can cause carbon monoxide levels to rise to dangerous levels.
Those exhaust fumes, say Conrad, had "easy access for reentry into the living quarters" through the fresh air vent.
"I would prefer that there be a better and bigger separation than that," said Terry Brennan, a 28-year building scientist who owns Camroden and Associates in Westmoreland, N.Y., referring to the three-foot HUD code.
"The amount of percentage of intake air goes down exponentially as you go away with distance," he said. "Ten feet away isn't three times less, it's 20 times less -- a big difference. It's hard to measure, but it's likely we have a lot of similar cases to this."
11,000 Undetected Carbon Monoxide Cases
The CDC reports that more than 600 Americans accidentally die each year of acute carbon monoxide poisoning. The gas is odorless and colorless.
"People can be overcome in a minute or so," said Dr. Philip Landrigan, a pediatrician at Mount Sinai School of Medicine in New York City. "All it takes is a few breaths."
It is equally dangerous in infants and adults. "Both go down pretty fast," he told ABCNews.com.
An estimated 11,000 cases of low-level carbon monoxide poisoning go undetected each year, according to a yearlong study at Rhode Island Hospital that was published in a 2008 issue of the Journal of Emergency Medicine.
That's because its symptoms -- headache, dizziness, chest pain, nausea and vomiting -- are often diagnosed as the flu.
Daniel's failure to feed properly was a "classic symptom," according to expert Greiner, who was not part of the Conrad investigation.
Carbon monoxide is a byproduct of combustion heating and air conditioning and must be properly vented.
Under international building codes, vents in a conventional home must be placed a minimum of 10 feet apart. But critics say local officials often ignore manufactured housing because it carries HUD's red seal of approval.
"You cannot expect consumers to be building scientists," said Rebecca Morely, executive director of the National Center for Healthy Housing. "Most people are not skilled enough to see if it's flawed."
"The larger issue is, is HUD the best regulator of the units?" she said. "There should be more oversight. Who is responsible for quality control for both health and safety?"
HUD spokesman Lemar Wooley told ABCNews.com that the Conrad complaint was the first the department had received about carbon monoxide dangers in manufactured homes.
HUD Looks at CO Warning
"Because these indoor air quality concerns have been raised, HUD will be looking into the matter and may refer this issue to its Manufactured Housing Consensus Committee to obtain their recommendations on whether the current requirements should be changed," he said in a statement.
About 8 million Americans live in manufactured homes -- once called mobile homes. Not all are installed with combustible gas furnaces, according to HUD.
In Utah, these homes are a cheap alternative to what residents in this economically struggling region call a "stick-built" house. At least 100 dot Sanpete County.
"Our economy is about the worst in the state," said Todd Mortensen, who owns Trade Winds Heating in Manti, which has a population of about 5,000. "This is how people live when you can't afford to have a house built."
A manufactured house can cost as little as $68,000; the property might cost $25,000, according to Mortensen.
Mortensen recommends a roof jack extension to raise the vents, "but you can't eliminate the problem 100 percent," he said.
In normal "thermal buoyancy" hot fuel gases rise above the roof and float into the air. But during the winter, dense, cold air can cause exhaust fumes to hover over the roof. And with certain wind currents and snow blocking vents, "it's like a perfect storm for it to happen," he told ABCNews.com.
Baby Showed Symptoms
Daniel Conrad was born at home with the help of a midwife in August 2007 with the home's air conditioning and hot water heater at full force. Looking back, his father says the newborn was listless and his mother was nauseated.
"He looked awful," said David Conrad, 47, and a self-employed day trader. But throughout the early fall, the baby thrived until the family turned on the heating system in October. By winter, the child was spitting up more milk than he was ingesting.
The Conrads' other kids were fine, though he said the family experienced some low-level nausea. Church members started to talk and reported the family to authorities.
"We had just moved here and they see we are giving a home birth and they find out we are vegan," said Conrad. "This wouldn't have happened in our previous place, where people knew us well and respected us. They were well-meaning but they didn't have the confidence we had. They thought we were harming our baby and were irresponsible."
Daniel was put under court-ordered doctor supervision, but wasn't tested for carbon monoxide poisoning. Rodgers, who founded the nonprofit LifeSave Biological Research, suggested carbon monoxide poisoning might be a possibility.
Together, he and Conrad blocked the intake vent with a plastic top and duct tape and opened a window to draw in fresh air, a quick solution they have shared with neighbors.
Boats, Buildings Can Poison
Since then, Conrad said Daniel has been "happy, healthy" and thriving physically. The state's case against the Conrads was dismissed in October.
Clark Watkin, an Arizona lawyer who handles cases of carbon monoxide poisoning, confirmed that "proximity of the intake and the exhaust is a factor -- whether it's a building structure, a boat, wherever there is a combustion engine."
"This is actually quite common," Watkin, who has no involvement in the Conrad case, told ABCNews.com. "Depending upon the force of the exhaust and whether there is any breeze directing the exhaust fumes away from the intake vent, you can have a dangerous situation."
Retired chemical engineer Jay Bishop of Bountiful, Utah, has joined Conrad's crusade to alert residents in Utah's 80,000 manufactured homes, many poor and some on American Indian reservations.
"We need to absolutely require 12 feet [between furnace vents]," he told ABCNews.com. "We are openly contesting this, informing people and hoping HUD will eventually change the regulations."
The Occupational Safety and Health Administration sets safe levels for carbon monoxide in the workplace at 35 part per million for eight-hour exposure. But some carbon monoxide alarms only sound at 400 ppm, according to Bishop, who spent 20 years helping the military conform to requirements by the Environmental Protection Agency.
Carbon Monoxide Alarms 'Worthless'
Most experts credit these detectors with saving lives, but, says Bishop, "Good grief, they are worthless."
When patients show signs of low-level poisoning, they are often dismissed by emergency rooms as having the flu. As in Daniel's case, they are rarely tested, according to Bishop.
As a result of Conrad's and Rodgers' efforts, Utah's State Sen. Margaret Dayton will introduce legislation. "I am hopeful that we can inform health-care providers about this issue and promote testing for carbon monoxide," she told ABCNews.com.
Rodgers has created a Web site for more information on the case at CarbonMonoxideAwareness.org.
Conrad's neighbors, who also live in manufactured homes, have taken preliminary steps to close off their intake valves, though none has reported cases of carbon monoxide poisoning.
Many of them supported the Conrads during their trial last year and have accompanied them to public hearings to push for more attention to the issue.
That, say the Conrads, might have helped Daniel get better faster and helped the family avoid the child abuse charges that nearly tore the family apart.
"I absolutely believe that was what was wrong with the child," said neighbor Greenhalgh, a father of three. "But Daniel looks like a different child now."