On Dec. 4, a winter storm moved into the Charlotte, N.C., region, bringing cold temperatures and rain. As night fell and temperatures dropped, torrential rain turned into ice that coated tree limbs and power lines up to a quarter of an inch thick. Large trees and limbs fell and power lines snapped all over the area. Between 8 p.m. and 8 a.m. the following day, the fire department ran 175 calls for downed power lines.

In fact, Dec. 5 became the busiest day for emergencies in the department's history, as fire companies responded to 847 alarms, more than four times the normal call load. With no electricity and temperatures in the low 20s, residents turned to non-standard heat sources for cooking and warmth. Inevitably, there was a spike in carbon monoxide detector activations and EMS calls in these homes. In all, the Charlotte Fire Department responded to 355 incidents involving carbon monoxide over six days.

Fortunately, the public safety and health agencies in Mecklenburg County were prepared. Fire companies are equipped with gas monitors, which were used extensively. Most importantly, the paramedics with MEDIC, the Mecklenburg County Emergency Medical Response Agency, and emergency room doctors accepted the fire department's carbon monoxide data and began appropriate treatment of victims immediately. There was only one death from carbon monoxide poisoning throughout the six-day crisis.

Making sure history doesn't repeat

The cooperation that made response to carbon monoxide calls successful was not accidental. In 1999, there were two deaths from carbon monoxide poisoning. Two members of a family died and several more were sickened when a malfunctioning furnace gave off carbon monoxide. In June 1999, the fire department responded to a call in a town-house complex to discover four people dead and three sickened by carbon monoxide from a car left running in an enclosed garage. Subsequent investigation by building code officials revealed no defects or problems with the four-unit structure.

These incidents were a wake-up call to local fire, EMS, building and public health officials. A task force with representatives from each service was convened to investigate and make recommendations on preventing future occurrences. They devised a five-point strategy for addressing the problem:

1. Increase public awareness of the risk of carbon monoxide poisoning and how to minimize that risk.

2. Increase physician awareness of carbon monoxide symptom misdiagnosis, which is a common problem.

3. Examine the risks of carbon monoxide to fire investigators at cold fire sites and take appropriate action to minimize such risk.

4. Train HVAC contractors in preventing carbon monoxide problems in heating and air conditioning systems.

5. Propose a carbon monoxide alarm ordinance to the County Commission, which has jurisdiction over building code issues, that would require carbon monoxide alarms in all homes with fossil fuel — burning appliances.

The ordinance became effective on Jan. 1, 2001. Not surprisingly, it has dramatically increased the number of carbon monoxide alarms to which the Charlotte Fire Department responds. (See “Charlotte CO detector calls,” page 76.) The department's hazmat teams always have carried multi-gas monitors, but with three fire companies in two stations, response in a reasonable time frame isn't always feasible.

Two-fold strategy

As the task force worked on the carbon monoxide ordinance, hazmat team leaders realized that engine companies, too, needed CO detection capabilities. They began to search for monitors that would work in emergency situations.

Initially the department issued colorimetric tubes to fire companies, but these did not work for emergency use. After an incident involving a below-grade rescue, the meter program was expanded to place four-gas meters on ladders and rescues. Response protocol at this time was to dispatch the closest ladder or rescue company to all carbon monoxide detector activations.

However, with the new county ordinance, the number of CO calls increased dramatically and placed a heavy response burden on the 15 fire companies that carried the four-gas meters. We reevaluated the program and decided to take the colorimetric tubes out of service and install the single-gas monitors on all engine companies. The department purchased 45 T82 meters from Industrial Scientific Corp. of Oakdale, Pa. These units were not designed originally to measure carbon monoxide levels at emergency scenes, so manufacturer engineers worked with the department to ensure that the meters would perform as needed.

At this point, all firefighters were required to attend an in-service class on meters and the proper used of air monitoring equipment. Because interpreting meter readings is a hazmat technician skill, the firefighters were trained to use the meters as a go/no go program. This allows them to meet OSHA regulations concerning entry into confined spaces.

Currently, the department's 36 engines have single-gas meters, while the 12 ladders, two rescues and three hazmat units use four-gas meters for confined-space rescue and carbon monoxide monitoring.

Data verification

All meters need to be periodically checked against a known quantity of product to ensure that the meter is reading accurately. As anyone who has ever calibrated meters knows, this process can sometimes leave room for error. Span values and correction factors can be wrong or misinterpreted, causing problems with the meters or sensors themselves. Has anyone ever had to return a meter because it was failing, only to have it come back from the manufacturer with a report that it only properly calibrated the meter? While we don't like to admit it, if we're honest with ourselves we can see how easy it is to make errors.

Charlotte CO detector calls

FY 98	246
FY 99	214
FY 00	253
FY 01	371
FY 02	821
FY 03	1,189 (July-March)
A countywide carbon monoxide alarm ordinance was put into effect on Jan. 1, 2001, for all homes with fossil fuel — burning units.

With different calibrations, different span settings and different correction factors, it's easy to make errors and not realize it. Charlotte's hazmat team researched several different available methods to streamline and simplify the whole meter maintenance and records-keeping process. After looking at various options, we made the decision to obtain the DS1000, also from Industrial Scientific Corp.

This model docking station is an automated instrument management system designed to reduce the time and costs spent manually calibrating instruments while reducing the liabilities associated with instrument maintenance and records keeping. Once installed, the station reduced the calibration process to six minutes per meter. This meant significant savings, as the meter program maintains all single-gas meters and 27 multi-gas meters. More efficient use allows the calibration to go farther than before.

There are 11 docking stations strategically located around the city to calibrate and verify the meters' accuracy without taking them out of service. The docking stations download the meters' data into a central database on the department's local area network and can be recalled and matched to a specific scene or location as needed. They also maintain a record of all calibrations and sensor settings. By tracking sensors over time, this feature allows us to predict with useful accuracy when a sensor is going into a marginal condition, allowing us to replace sensors as needed and not wait for failure.

All companies are required to calibrate their meters monthly. Station 13, home of the original hazmat companies, is the meter program contact point for all needed repairs. Their docking station has additional software that keeps a real-time connection with the meter manufacturer. Several times, the manufacturer engineers have noticed sensors going into marginal mode and have called to advise us of the problems. Thus, sensors were replaced before the meter failed in the field.

Plans in action

Certainly the detectors were the backbone of the fire department's response to carbon monoxide calls during the December ice storm. They provided immediate baseline data on carbon monoxide levels in homes that enabled firefighters to protect themselves and begin treatment of affected victims. For example:

• “The reading was 50ppm in the apartment and there was a battery detector present that alerted the occupants,” reported Capt. Glyn Hasty of Ladder 1 “There were no victims, due to the activation.”
• “A charcoal grill placed in the middle of the living room was the source with a peak reading of approximately 478ppm in living room,” wrote Capt. Lance Foulk of Ladder 26.
• “The resident's alarm activated and showed 40ppm when we arrived,” reported Capt. Bruce Pickett of Engine 7. “Neither the resident nor his wife had any symptoms. Upon monitoring the residence we found a reading of 50ppm in a closed bedroom, 42ppm in another room, and 40ppm in the hallway. The residence was without power and the resident had been running a generator outside the residence. The generator was in a sunken drive leading to his basement and apparently the CO came in through the basement or the windows on that side of the house.”
• “Two were transported to Carolinas Medical Center. Ladder 29 was used for ventilation (electric fan),” noted Capt. Frank Robinson of Engine 3. “The CO reading was 180ppm. Gasoline generator in back yard against house with exhaust facing house and sitting in about 8 inches of leaves. Two propane lights and a kerosene heater were almost out of fuel. The exhaust vent for the dryer was near the running generator and was open from excessive lint.”
• “One victim transported unconscious, as well as three other family members complaining of headache and sickness,” detailed Capt. Robert Hunt of Engine 17. “CO level of 28. This was attributed to multiple candles in a small shut-up bedroom with the door shut. CO level dropped quickly when ventilated.”
• “CO reading at 782 on monitor, four patients transported, two priority one, source was charcoal in grill located in kitchen,” wrote Bttn. Chief Jim Thompson of Battalion 3.

In many homes where carbon monoxide was reported, charcoal grills, generators and other unvented appliances were being used to provide heat in the absence of electrical power. While that may be acceptable practice in places where houses aren't so tightly insulated, it caused problems in Charlotte.

The local media cooperated with fire and health department officials in broadcasting warnings about the dangers of carbon monoxide and the hazards of non-traditional heating methods, but these didn't necessarily reach those who don't speak English or whose lack of electricity meant that they could not receive TV or radio broadcasts. In fact, the one death from carbon monoxide poisoning was a French-speaking woman.

As a result, the carbon monoxide task force is exploring the possibility of requiring carbon monoxide detectors in all residential properties, not just those with fossil-fuel burning appliances.

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Garry McCormick is a battalion chief in the Charlotte (N.C.) Fire Department. He has previously served as a captain on the hazmat response team.

Sally Young is the Charlotte Fire Department's planning officer.