Eventually, both types of detectors will remain on campus.
"We certainly hope that we have done everything that would guard against this, but you can never be 100 percent sure," Gereaux said.
Check the furnace first
In 2002, the Gas Technology Institute, a research and training organization for the gas industry, presented Clifford's findings to the U.S. Consumer Product Safety Commission, which decided to do its own study.
The commission found that while the alarms did not always respond within the time limit required by industry standards, "they did not alarm so late as to expose consumers to a significant health risk." However, the commission recommended that the industry standard be strengthened to address several problems found in the study.
Between 1994 and 2004, the commission investigated 38 complaints of carbon monoxide detectors that failed to warn of hazardous conditions. Six of those investigations led to the recall of more than 1.3 million alarms.
Still, the commission encourages consumers to purchase carbon monoxide alarms for their homes.
"Even though in the past there have been problems with the alarms, they still should be used because they provide a good level of protection from carbon monoxide incidents," said commission spokesman Mark Ross.
The alarms are recommended as a secondary defense against poisoning; the most important precaution is the proper installation and regular inspection of fuel-burning appliances, the commission said.
Brand names were not included in the Gas Technology Institute study, which mirrored the results of earlier tests of carbon monoxide alarms by the institute and other organizations. The intent was to inform manufacturers of problems and not to endorse or denounce a specific brand, Clifford said.
Responding to tragedies
Only about 29 percent of homes in the United States have carbon monoxide detectors, the Home Safety Council estimates.
But the number could increase as more state and local governments pass laws and ordinances requiring installation of the alarms. Since 2000, at least 11 states have passed such laws, according to the National Conference of State Legislatures. Even more cities and counties have enacted similar requirements.
Much of the legislation was inspired by tragedies such as the one at Roanoke College. In Massachusetts last year, the legislature passed "Nicole's Law," named after 7-year-old Nicole Garofalo, who died from carbon monoxide poisoning when snowdrifts clogged a boiler vent outside her home.
In Virginia, Sen. Frank Ruff, R-Mecklenburg County, raised the issue at the urging of a constituent who nearly died during a beach vacation when carbon monoxide from a heated swimming pool seeped into a rental home.
Ruff's bill, a proposed expansion of the Landlord Tenant Act, would affect only rental homes with carbon-based fuel appliances and those with attached garages or adjacent to parking spaces.
"When I drew it up, I wasn't trying to solve all the problems in the world," Ruff said. "My goal was just to get it in the public realm."
That was before Walter Vierling, a 91-year-old retired pastor from Giles County, was found dead in a dorm room at Roanoke College. Vierling was attending a Lutheran church conference at the school. More than 100 people -- including members of Vierling's church group and teenage girls enrolled in a college prep program -- were treated at local hospitals after experiencing nausea and dizziness from the gas leak.
Last week, new details emerged. It took rescue workers more than three hours to find Vierling's body and two women sickened by the gas because their rooms were missed during an initial search of the dorm, according to written reports from the Salem Fire-EMS Department.
At the time of the carbon monoxide buildup, there were no detectors in place to warn residents.