October and the end of daylight savings time bring the annual reminders to replace the batteries in smoke and carbon monoxide detectors. Late last winter, in the wee hours of a freezing cold January morning, Carol Mallia, RN and associate director in the MNA's department of nursing, learned just how valuable a working carbon monoxide detector really is.

A faint, unfamiliar chirping sound woke Mallia that night, and reluctantly she got out of her warm bed to locate the noise. On her way down the stairs she recalled changing the batteries in the detectors on the first and second floor within the past month when the low battery tone had sounded. But had she remembered the one in the basement? As she slid the detector off the basement ceiling, she fully expected it to read "low battery." Much to her surprise it was flashing "Go to Fresh Air."

She recalled that the wood stove had been running all day but knew that it had gone out some time in the night. She also remembered that there was no smoky downdraft odor to indicate a problem. In disbelief she changed the battery, checked the kids and called the non-emergency number of the local fire department. She was fully convinced that this was going to be an embarrassing false alarm.

Within minutes the fire department arrived, with sirens blaring. The firefighters quickly donned heavy coats and full face breathing apparatus. Once in the house, their instruments detected carbon monoxide at a dangerous level on the first floor and Mallia was instructed to evacuate immediately.

Mallia and her husband scooped up their sleeping children, ages 4 and 8; grabbed coats and blankets; and out the door they went. Where would they go in the middle of a winter night? Into the car, of course. Mallia and her husband got the heater going and warmed up their sleepy, and slightly perplexed, children.

Mallia said the real surprise was to realize the extent of the danger they were in and to learn of the precautions that the fire department was taking for their own safety while they checked out the house.

And check it out they did. Sure enough, detector instruments noted toxic levels throughout the basement, highest near the wood stove. The first floor levels were in the danger zone and the second floor (where the bed rooms are located) were just mildly elevated. The woodstove in the basement den was identified as the source. Apparently the wood burned out and with the extreme cold temperatures (2 degrees below zero that night), it had created a downdraft of gases.

The firefighters proceeded to ventilate the house with large fans. After 45 minutes of blowing the artic temperatures into the house, they re-checked the levels and gave Mallia and her family the okay to return inside.

The firefighters explained to Mallia that the family was very fortunate. Since carbon monoxide can get into the heating system, it could have circulated throughout the house via their forced hot-air system.

Mallia told us that she made a few changes after that night. She installed an electric carbon monoxide detector with digital level readout and a battery back up. She still uses her wood stove, but ensures it is completely extinguished before going to sleep.

When Mallia shared this story with us at MNA the day after the incident, I asked her if we could write it up for the Massachusetts Nurse, since it just might serve to save another reader's family. Mallia was willing to share this story and reminds everyone to replace the batteries in their detectors in the spring and fall; to test the detector as directed; and to call 911 and get out quickly if the detector alarm sounds.

For more information, visit the Department of Fire Services' Web site at www.mass.gov/dfs/index.shtm, or the CDC's Web site at www.bt.cdc.gov/disasters/carbonmonoxide.asp