fast facts Smoke Detectors Provide Early Warning of Danger March 2010 

Office of Compliance 

advancing safety, health, and workplace rights in the legislative branch 

www.compliance.gov 

TOXIC GASES IN SMOKE 

The cause of death and injury in a fire is mainly due to smoke 

inhalation and not actual contact by flames, unless a person is 

extremely close to the fire location. According to the National 

Fire Protection Association (NFPA) Fire Analysis & Research 

Division, about two-thirds of all fatal injuries in fires are due to 

smoke inhalation, possibly in combination with other fire 

effects, with more than half of such deaths attributed to smoke 

inhalation alone. Smoke is a typical by-product of fire that may 

be accompanied by carbon monoxide and other toxic gases 

depending on the nature of the burning material. When exposed 

to toxic gases and smoke, a person will usually experience 

headaches and nausea, then partial incapacitation that reduces a 

person’s chance of escape, followed by loss of consciousness 

and danger of death depending on the concentration of toxic 

gases and length of time of the exposure. 

 

SMOKE ALARM VS. SMOKE DETECTOR 

Both smoke alarms and smoke detectors work by detecting tiny 

smoke particles and gases given off when a combustible material burns. Smoke alarms (most common in residential buildings) immediately sound the alarm when a high concentration 

of smoke is detected. Smoke detectors (most common in businesses) are one component of an alarm system with a fire panel. 

Sounding the alarm, smoke detectors typically transmit a signal 

to the control panel to notify and allow an official to investigate 

an area where a detector has been activated. During this time, 

the alarm system may initiate other actions such as closing fire 

doors and activating the building’s smoke controls. If three 

minutes pass without an assessment of potential fire, the Life 

Safety Code NFPA 101 and NFPA 72 require that the building’s fire alarm system be programmed to automatically trigger 

an evacuation alarm.

INOPERABLE SMOKE DETECTORS 

Blocked and Covered 

When ceilings and pipes 

are repainted, nearby 

smoke detectors are usually covered to make sure 

no paint gets onto the 

detectors. A smoke detector will not function properly until the bag is 

removed. Figure 1 shows 

a photo of an active smoke 

detector covered with a plastic bag that was not removed 

after the painting was complete. 

New smoke detectors are 

usually protected with a 

plastic cover as shown in 

Figure 2 to prevent the 

smoke detector from accumulating dust during shipping and installation. 

However, this cover must 

be removed immediately 

after the work is completed in the area and the smoke detector is activated. 

Smoke detectors are covered temporarily to prevent 

operation during construction work in the area, but the 

cover needs to be removed when the work is finished. 

These blocked and covered conditions demonstrate the 

importance of periodic inspection of fire protection systems to ensure that they are maintained in serviceable 

condition.

Figure 1: Covered Smoke Detector 

Figure 2: New Smoke Detector 

Smoke and other combustion products are the first signs of a potential fire. Thus, detecting smoke particles or toxic combustion gases is one of the fastest known ways to alert people 24/7 to the existence of a potential fire. This will provide more 

time for a safe evacuation. Automatic detection devices, such as smoke detectors, that are properly installed and maintained, 

play a vital role in reducing fire deaths and injuries in workplaces and homes. Since the late 1970's, smoke detectors contributed to an almost 50 percent decrease in fire deaths. Therefore, it is imperative to make sure that smoke detectors and smoke 

alarms are present and in good working condition for the protection of life and property. 
fast stats 

2000-2004: 43% of all home fire deaths resulted from fires in homes with no smoke alarms, while 22% resulted from fires in 

 homes where smoke alarms were present but did not operate. The death rate per 100 reported fires was twice as 

 high in homes without a working smoke alarm as it was in homes with a working smoke alarm. 

*Source: NFPA Fire Analysis and Research Division 

2003-2007: Of the thousands of occupational fatalities that occurred during this four year period, 86 of those were caused by 

 smoke inhalation. (Smoke inhalation fatalities are defined as those caused by poisoning and toxic effects, smoke, 

and fire gases.) 

*Source: United States Department of Labor, Bureau of Labor Statistics 

Occupational Safety and Health Administration (OSHA) Standards require: 

Each employer to provide and maintain an employee alarm system. This employee alarm system must notify each employee 

that there is an emergency and must be kept in an operable condition throughout the building or work area. (29 CFR§ 1910.37

(e)). The OSHA employee alarm standard also requires tactile alerting devices that may be used for those employees who would 

not perceive the emergency alarm via lighting nor sounding devices. (29CFR§1910.165) 

 

 

This information does not constitute advice or an official ruling of the Office of Comp liance or the Board of Directors and is 

intended for educational purposes only. For further information, please refer to the Congressional Accountability Act (2 U.S.C.

1301 et seq.) and the regulations issued by the Board, or you may contact the Office of Compliance.

The Office of Compliance advances safety, health, 

and workplace rights in the U.S. Congress and the 

Legislative Branch. Established as an independent 

agency by the Congressional Accountability Act of 

1995, the Office educates employees and employing 

offices about their rights and responsibilities under 

the Act, provides an impartial dispute resolution 

process, and investigates and remedies violations of 

the Act. 

If you have any questions, please do not hesitate to 

contact the Office of Compliance: 

Room LA 200, John Adams Building 

110 Second Street, SE 

Washington, D.C. 20540 

t/ 202-724-9250 

tdd/ 202-426-1912 

f/ 202-426-1913 

Peter Ames Eveleth 

General Counsel 

Mary-Margaret Smith 

Editor 

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Missing, disconnected, or dead battery 

Missing or disconnected batteries are the leading cause of smoke alarm failures. Frequently, the owners remove or disconnect batteries because of nuisance activations. NFPA reports show that more than half (54%) of the smoke alarm 

failures were due to missing or disconnected batteries and 19% were due to dead batteries. There is a simple test button 

on most smoke alarms that can be pressed to make sure the smoke alarm is properly working. If the test button does not 

work, the battery should be checked and replaced as necessary. It is recommended that when we change our clocks for 

daylight savings purposes, approximately every six months, we also test or change the batteries in our smoke detectors.