Topical Fire Report Series

U.S. Department of Homeland Security • U.S. Fire Administration 

National Fire Data Center • Emmitsburg, Maryland 21727 

www.usfa.fema.gov/statistics/

Volume 15, Issue 10 / March 2015

One- and Two-Family Residential 

Building Basement Fires (2010-2012)

These topical reports are designed to 

explore facets of the U.S. fire problem as 

depicted through data collected in the U.S. 

Fire Administration’s National Fire Incident 

Reporting System. Each topical report 

briefly addresses the nature of the specific 

fire or fire-related topic, highlights important findings from the data, and may suggest other resources to consider for further 

information. 

Findings

■ An estimated 6,500 one- and two-family residential building basement fires were 

reported to fire departments within the United States each year and caused an 

estimated 65 deaths, 400 injuries and $278 million in property loss.

■ One- and two-family residential building basement fires are considered part of the 

residential fire problem, and they comprised about 3 percent of all one- and twofamily residential building fires. 

■ The leading reported causes of one- and two-family residential building basement 

fires were “electrical malfunction” (19 percent); “heating” (14 percent); “appliances” 

(12 percent); and “other unintentional, careless” actions (12 percent).

■ January (12 percent) was the peak month for one- and two-family residential building 

basement fires, followed by December (10 percent) and February (10 percent). 

■ Electrical arcing was the most common heat source in residential building 

basement fires (19 percent).

From 2010 to 2012, an estimated 6,500 one- and twofamily residential building fires originating in basements were reported annually by U.S. fire departments. 

These fires caused an estimated 65 deaths, 400 injuries and 

$278 million in property damage each year.1, 2, 3 Basement 

fires accounted for about 3 percent of all one- and two-family residential building fires reported to the National Fire 

Incident Reporting System (NFIRS) from 2010 to 2012. 

In NFIRS, one- and two-family residential building basement fires are defined as those fires where the property 

use was reported to be a one- or two-family dwelling, and 

the story of fire origin was noted to be one or two stories 

below grade. The intent is to focus on single-family and 

duplex housing with a typical foundation basement.4

Basements associated with single-family and duplex houses 

may or may not have been designed to be finished and 

converted into living/recreational/sleeping/workshop areas, 

especially those homes built before World War II. They are 

frequently used for storage, as well as a location for major 

household utilities and appliances, including furnace, water 

heater, workshop and laundry areas. Whether intentionally 

or unintentionally, unsupervised children and teenagers may 

create fire hazards. Frequently associated with ad hoc residential use are several types of portable equipment — space 

heaters, dehumidifiers, microwave and/or toaster ovens, and 

even entertainment centers. If a basement was not converted 

from “unfinished” to “finished” in accordance with local 

codes, then these items might be plugged into undergauge 

extension cords and worn-out power strips. 

Home fire safety material available from the U.S. Fire 

Administration (USFA) recommends that all basements 

include smoke alarm and sprinkler systems. Be aware of 

basement-related fire hazards, including combustible materials near open flame in water heaters and frayed wires on 

light bulbs, among other potential hazards.5

Although beyond the scope of this report, basement 

fires present significant safety issues for firefighters. An 

Underwriters Laboratory (UL) study in conjunction with 

the National Institute of Standards and Technology (NIST) 

established the universal instability of all types of floor construction during a basement fire. There are no reliable and 

repeatable warning signs of collapse, and there is no way to 

know when it is safe to operate on top of a basement fire.6

In addition to unpredictable changes in flow paths, other 

aspects of basements that pose threats to firefighters include 

limited access, cluttered storage, and nonstandard room and 

furnishings arrangement. 
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 2

This topical report addresses the characteristics of one- and 

two-family residential building basement fires, as reported 

to NFIRS from 2010 to 2012. The NFIRS data is used for the 

analyses presented throughout the report.7

 For the purpose 

of the report, the terms “one- and two-family residential 

fires” and “basement fires” are synonymous with “one- and 

two-family residential building fires” and “one- and twofamily residential building basement fires,” respectively. 

“Basement fires” is used throughout the body of this report; 

the findings, tables, charts, headings and endnotes reflect 

the full category, “one- and two-family residential building 

basement fires.”

Type of Fire

Building fires are divided into two classes of severity in 

NFIRS: “confined fires,” which are fires confined to certain 

types of equipment or objects, and “nonconfined fires,” 

which are not confined. Confined building fires are small 

fire incidents that are limited in extent, staying within pots, 

fireplaces or certain other noncombustible containers.8

Confined fires rarely result in serious injury or large content 

loss and are expected to have no significant accompanying property loss due to flame damage.9

 Of the two classes 

of severity, nonconfined fires accounted for 93 percent of 

basement fires. The smaller, confined fires accounted for the 

remaining 7 percent (Table 1). 

Most NFIRS fire data analyses compare and contrast confined versus nonconfined building fires. However, basement 

fires are defined in part by the story of fire origin, which is 

only required to be reported for nonconfined fires. For confined fires, the story of fire origin is reported on an optional 

basis. As such, there is no way to meaningfully compare 

confined versus nonconfined basement fires. Therefore, the 

subsequent analyses in this report reflect all basement fires 

in one- and two-family dwellings and do not distinguish 

between confined and nonconfined fires.

Table 1. One- and Two-Family Residential Building Basement Fires by Type of Incident 

(2010-2012) 

Incident Type Percent

Nonconfined fires 92.8

Confined fires 7.2

Total 100.0

Source: NFIRS 5.0.

Loss Measures

Table 2 presents losses, averaged over the three-year period 

from 2010-2012, of reported basement and nonbasement 

residential fires.10 Loss measures per fire should be compared with other broad categories of fire with caution, as 

the two are not directly comparable. Basement fires caused 

20 percent more fatalities per 1,000 fires, 77 percent more 

injuries per 1,000 fires, and 91 percent greater dollar loss 

per fire than nonbasement fires (Table 2). Although these 

differences may be due to how the data are collected, 

especially confined versus nonconfined fires as previously 

outlined, this is still a compelling difference between 

basement fires and other one- and two-family residential 

building fires. 

Table 2. Loss Measures for One- and Two-Family Residential Building Basement and 

Nonbasement Fires (Three-Year Average, 2010-2012)

Measure One- and Two-Family 

Residential Building Basement Fires

One- and Two-Family 

Residential Building Nonbasement Fires

Average Loss

Fatalities/1,000 fires 7.9 6.6

Injuries/1,000 fires 49.7 28.1

Dollar loss/fire $34,220 $17,910

Source: NFIRS 5.0.

Notes: 1. Average loss for fatalities and injuries is computed per 1,000 fires. Average dollar loss is computed per fire and rounded to the nearest $10.

2. When calculating the average dollar loss per fire for 2010-2012, the 2010 and 2011 dollar-loss values were adjusted to their equivalent 2012 dollar-loss values to account for inflation.
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 3

When Residential Building Basement Fires 

Occur

As shown in Figure 1, basement fires occurred most frequently in the late afternoon to early evening hours from 

3 to 9 p.m., accounting for 32 percent of the fires.11 This 

period includes a notable peak from 3 to 4 p.m., which may 

be associated with activity typical of school age children 

after school, including heating snacks and turning on space 

heaters. Fires gradually declined throughout the late evening and early morning hours, reaching the lowest point 

from 5 to 6 a.m. Beginning at 6 a.m., fire incidence started 

to increase until the peak hours were reached. 

Figure 1. One- and Two-Family Residential Building Basement Fires by Time of Alarm 

(2010-2012)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

11PM-Mid

10PM-11PM

9PM-10PM

1PM-2PM2PM-3PM3PM-4PM4PM-5PM5PM-6PM6PM-7PM7PM-8PM8PM-9PM

12PM-1PM

10AM-11AM

11AM-12PM

9AM-10AM

Mid-1AM

1AM-2AM2AM-3AM3AM-4AM4AM-5AM5AM-6AM6AM-7AM7AM-8AM8AM-9AM

Time of Alarm

Percent of One- and Two-Family

Residential Building Basement Fires

3.6 3.3

2.8 2.9 3.0

2.6

3.0

3.4 3.4

3.7

4.2

4.6

5.5 5.3 5.2

4.7

4.4

3.8

4.6

5.0

5.7

5.3 5.4

4.7

Source: NFIRS 5.0.

Note: Total does not add up to 100 percent due to rounding.

Figure 2 illustrates that basement fires have a substantial 

peak in January at 12 percent, followed by December and 

February, each at 10 percent. The increase in basement 

fires during these peak months was driven by an increase 

in heating fires and other unintentional, careless actions. 

Electrical malfunction, the leading cause of basement fires 

throughout the year, remained fairly constant throughout 

the year, while the next three leading causes — heating, 

unintentional and careless actions, and appliances — varied 

considerably throughout the year. The lowest incidence of 

basement fires occurred in September, when fires caused by 

heating, and unintentional and careless actions, were well 

below their monthly average (data not shown).12

Figure 2. One- and Two-Family Residential Building Basement Fires by Month (2010-2012)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

November

December

October

September

August

July

April

May

June

March

February

January

Month of Year

Percent of One- and Two-Family 

Residential Building Basement Fires

11.6

9.6

8.8

7.9 7.3 7.4 7.8 7.4 7.7

8.4

9.9

6.4

Source: NFIRS 5.0.

Note: Total does not add up to 100 percent due to rounding.
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 4

Causes of One- and Two-Family Residential 

Building Basement Fires

Figure 3 shows the causes of basement fires.13, 14 Electrical 

malfunctions caused 19 percent of all basement fires. This 

finding suggests that homeowners and residents should 

make it a priority to have electrical equipment and electrical 

wiring in basements professionally installed, inspected and 

maintained.

The next three leading reported causes combined accounted 

for 38 percent of basement fires: heating (14 percent); appliances (12 percent); and other unintentional, careless actions 

(12 percent). 

Figure 3. One- and Two-Family Residential Building Basement Fires by Cause (2010-2012)

Percent of One- and Two-Family Residential Building Basement Fires

0.0 5.0 10.0 15.0 20.0 25.0 30.0

Unknown

Cause Under Investigation

Other Unintentional, Careless

Equipment Misoperation, Failure

Exposure

Natural

Other Equipment

Other Heat

Open Flame

Appliances

Electrical Malfunction

Cooking

Heating

Smoking

Playing with Heat Source

Intentional

Percent of all One- and Two-Family 

Residential Building Basement Fires 

With Cause Determined

Percent of all One- and Two-Family 

Residential Building Basement Fires

0.7

1.0

4.9

6.4

2.3

1.8

13.9

10.6

2.0

1.5

19.0

14.5

9.3

12.2

6.5

8.5

6.3

1.1

4.8

0.8

4.3

5.7

0.8

0.6

4.7

6.1

8.9

11.7

2.7

2.1

23.9

Causes Source: NFIRS 5.0.

Notes: 1. Causes are listed in order of the USFA Structure Fire Cause Hierarchy for ease of comparison of fire causes across different aspects of the fire problem. Fires are assigned to one of 16 cause 

groupings using a hierarchy of definitions, approximately as shown in the chart above. A fire is included in the highest category into which it fits. If it does not fit the top category, then the second 

one is considered, and if not that one, the third and so on. For example, if the fire is judged to be intentionally set and a match was used to ignite it, it is classified as intentional and not open flame 

because intentional is higher in the hierarchy.

2. Totals do not add up to 100 percent due to rounding.

Fire Spread in Residential Building 

Basement Fires

Fires that originate in the basement can be especially hazardous, as the natural convection of the flames may contribute to the fire’s spread to additional sources of fuel. As 

shown in Figure 4, basement fires are hazards, which is evident in the extent of fire spread: Of basement fires, 24 percent were limited to the object of origin, 36 percent were 

limited to the room of origin, 38 percent spread beyond 

the room of origin to the floor or building, and 2 percent 

of fires originating in basements spread beyond the building. Although not directly comparable and thus not depicted 

on this figure, due to the nature of how basement fires are 

identified, this is substantially different than the fire spread 

profile for all one- and two-family residential building fires 

where 48 percent were limited to the object of origin, 21 

percent were limited to the room of origin, 28 percent 

spread beyond the room of origin to the floor or building, 

and 4 percent of fires spread beyond the building.15, 16
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 5

Figure 4. Extent of Fire Spread in One- and Two-Family Residential Building Basement Fires 

(2010-2012)

Percent of One- and Two-Family Residential Building Basement Fires

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0

Beyond Building of Origin

Limited to Building of Origin

Limited to Floor of Origin

Limited to Room of Origin

Limited to Object of Origin 23.7

35.5

10.4

28.0

2.4

Source: NFIRS 5.0.

How One- and Two-Family Residential 

Building Basement Fires Start (Heat 

Source)

Figure 5 shows sources of heat categories in basement fires. 

The “heat from powered equipment” category accounted 

for 59 percent of all basement fires. Within this category, 

electrical arcing accounted for 19 percent; heat from other 

powered equipment accounted for 17 percent; radiated or 

conducted heat from operating equipment accounted for 

12 percent; and sparks, embers or flames from operating 

equipment accounted for 10 percent of all basement fires.17

The “heat from open flame or smoking materials” and “hot 

or smoldering object” categories each accounted for 13 percent of basement fires. The top three specific heat sources 

from these combined groupings were “hot ember or ash” 

(6 percent); “hot or smoldering object, other” (6 percent); 

and “heat from other open flame or smoking materials” 

(4 percent).

Figure 5. Sources of Heat in One- and Two-Family Residential Building Basement Fires 

by Major Category (2010-2012)

Percent of One- and Two-Family Residential Building Basement Fires

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0

Undetermined

Explosives, Fireworks

Multiple Heat Sources

 Including Multiple Ignitions

Heat Spread From Another Fire

Chemical, Natural Heat Source

Other Heat Source

Hot or Smoldering Objects

Heat From Open Flame

 or Smoking Material

Heat From Powered Equipment

Percent of One- and Two-Family 

Residential Building Basement Fires 

With Heat Source Determined

Percent of all One- and Two-Family 

Residential Building Basement Fires

41.1

58.6

13.4

9.4

12.7

8.9

3.9

5.5

4.8

4.0

3.4

0.6

2.8

0.5

0.4

0.3

29.8

Source: NFIRS 5.0.

Note: Total for one- and two-family residential building basement fires with heat source determined does not add up to 100 percent due to rounding.
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 6

What Ignites First in One- and Two-Family 

Residential Building Basement Fires

As shown in Table 3, the leading specific items most often 

first ignited in basement fires were “electrical wire, cable 

insulation” (13 percent); “structural member or framing” (12 

percent); and “wearing apparel not on a person” (8 percent). 

Of interest, fires involving “dust, fiber, lint, including sawdust and excelsior” accounted for 5 percent of basement fires. 

Table 3. Leading Items First Ignited in One- and Two-Family Residential Building 

Basement Fires (2010-2012)

Item First Ignited Percent

(Unknowns Apportioned)

Electrical wire, cable insulation 12.6

Structural member or framing 12.0

Wearing apparel not on a person 7.9

Item first ignited, other 6.3

Dust, fiber, lint, including sawdust and excelsior 5.2

Source: NFIRS 5.0.

Note: In 30 percent of the one- and two-family residential building basement fires, the item first ignited was specified as unknown.

Factors Contributing to Ignition in Oneand Two-Family Residential Building 

Basement Fires

Table 4 shows the categories of factors contributing to ignition in basement fires. The leading category was “misuse 

of material or product” (32 percent). In this category, heat 

source too close to combustibles (14 percent) and abandoned or discarded materials or products (6 percent) were 

the leading specific factors that accounted for 20 percent of 

basement fires. 

The “electrical failure, malfunction” category was a contributing factor in 27 percent of basement fires. The leading 

specific factor contributing to ignition in this category was 

other electrical failure, malfunction (13 percent), followed 

by unspecified short-circuit arc (7 percent). “Operational 

deficiency” was the third leading factor contributing to 

ignition category at 15 percent. 

Table 4. Factors Contributing to Ignition for One- and Two-Family 

Residential Building Basement Fires by Major Category 

(Where Factors Contributing to Ignition Are Specified, 2010-2012)

Factors Contributing to Ignition Category Percent of One- and Two-Family 

Residential Building Basement Fires

Misuse of material or product 31.6

Electrical failure, malfunction 26.9

Operational deficiency 14.7

Mechanical failure, malfunction 14.2

Natural condition 5.0

Other factors contributing to ignition 4.8

Fire spread or control 3.7

Design, manufacture, installation deficiency 2.8

Source: NFIRS 5.0.

Notes: 1. Includes only incidents where factors that contributed to the ignition of the fire were specified.

2. Multiple factors contributing to fire ignition may be noted for each incident; the total will exceed 100 percent.
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 7

Alerting/Suppression Systems in One- and 

Two-Family Residential Building Basement 

Fires

Technologies to detect and extinguish fires have been major 

contributors to the drop in fire fatalities and injuries over 

the past 35 years. Smoke alarms are now present in the 

majority of residential buildings. In addition, the use of 

residential sprinklers is widely supported by the fire service 

and is gaining support within residential communities.

Smoke Alarm Data

Smoke alarm data presented in Tables 5 and 6 are the 

raw counts from the NFIRS dataset and are not scaled to 

national estimates of smoke alarms in one- and two-family 

residential buildings where basement fires occurred. In 

addition, NFIRS does not allow for the determination of 

the type of smoke alarm — that is, if the smoke alarm was 

photoelectric or ionization — or the location of the smoke 

alarm with respect to the area of fire origin. Because NFIRS 

does not collect information on the location of the smoke 

alarm with respect to the area of fire origin, many smoke 

alarms may be located in the above grade floors of the residence and not necessarily in the basement.

Overall, smoke alarms were present in 57 percent of residences where basement fires occurred — both occupied 

and unoccupied — and were known to have operated in 

36 percent of the fires. In 18 percent of basement fires, no 

smoke alarms were present. In another 25 percent of these 

fires, firefighters were unable to determine if a smoke alarm 

was present (Table 5).

While 11 percent of all basement fires occurred in one- and 

two-family residential buildings that are not currently or 

routinely occupied, these buildings — which are under 

construction, undergoing major renovation, vacant and the 

like — are unlikely to have alerting and suppression systems that are in place and, if in place, that are operational. 

In fact, only 14 percent of all basement fires in unoccupied 

residential buildings were reported as having smoke alarms 

that operated.18 In addition, automatic suppression systems 

were reported as present in less than 1 percent of basement fires in residential buildings that were not routinely 

occupied. As a result, the detailed smoke alarm and automatic extinguishing system (AES) analyses in the next two 

sections of the report focus on basement fires in occupied 

residential buildings only.

Table 5. NFIRS Smoke Alarm Presence in One- and Two-Family Residential Building 

Basement Fires (2010-2012)

Presence of Smoke Alarms Count Percent

Present 8,027 56.8

None present 2,597 18.4

Undetermined 3,512 24.8

Total incidents 14,136 100.0

Source: NFIRS 5.0.

Note: The data presented in this table are raw data counts from the NFIRS dataset. They do not represent national estimates of smoke alarms in one- and two-family residential building basement fires. They are 

presented for informational purposes. 

Smoke Alarms in Occupied One- and Two-Family 

Residential Building Basement Fires

Smoke alarms were reported as present in 61 percent of 

basement fires in occupied one- and two-family residential 

buildings (Table 6). Smoke alarms were known to have 

operated in 39 percent of basement fires in occupied residential buildings, and they were known to be absent in 15 

percent. Firefighters were unable to determine if a smoke 

alarm was present in another 24 percent of these fires.

When operational status is considered, the percentage of 

smoke alarms reported as present (61 percent) consisted of:

•	 Present and operated — 39 percent.

•	 Present but did not operate — 15 percent (alarm failed 

to operate, 7 percent; fire too small, 7 percent).19

•	 Present but operational status unknown — 7 percent.

When the subset of incidents where smoke alarms were 

reported as present was analyzed separately as a whole, smoke 

alarms were reported to have operated in 65 percent of these 

incidents. The alarms failed to operate in 12 percent of these 

incidents, and the fire was too small to activate the alarm in 

another 12 percent. The operational status of the alarm was 

undetermined in an additional 11 percent of these incidents.

Nationally, only 3 percent of households lack smoke 

alarms.20 One of the most important values of smoke alarms 

is detecting smoldering fires before they break into open 

flame or produce large volumes of smoke. Smoke alarms 

could be especially useful in early detection of basement 

fires if the alarm is properly placed. Properly installed and 

maintained smoke alarms provide an early warning signal to household members in the event that a fire occurs. 

Smoke alarms help save lives and property.
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 8

USFA continues to partner with other government agencies and fire service entities to improve and develop new 

smoke alarm technologies. More information on smoke 

alarm technologies, performance, disposal and storage, 

training bulletins, and public education and outreach materials is available at http://www.usfa.fema.gov/prevention/

technology/smoke_fire_alarms.html.

Table 6. NFIRS Smoke Alarm Data for Occupied One- and Two-Family Residential Building 

Basement Fires (2010-2012)

Presence of 

Smoke Alarms Smoke Alarm Operational Status Smoke Alarm Effectiveness Count Percent

Present

Fire too small to activate smoke alarm 920 7.3

Smoke alarm operated

Smoke alarm alerted occupants, occupants responded 3,642 29.1

Smoke alarm alerted occupants, occupants failed to respond 129 1.0

No occupants 575 4.6

Smoke alarm failed to alert occupants 118 0.9

Undetermined 462 3.7

Smoke alarm failed to operate 928 7.4

Undetermined 860 6.9

None present 1,907 15.2

Undetermined 2,990 23.9

Total incidents 12,531 100.0

Source: NFIRS 5.0.

Note: The data presented in this table are raw data counts from the NFIRS dataset. They do not represent national estimates of smoke alarms in basement fires in occupied one- and two-family residential buildings. 

They are presented for informational purposes. 

Automatic Extinguishing System Data

Residential sprinklers are the primary AESs in residences 

but are not yet widely installed. In fact, full or partial AESs 

were reported as present in only 1 percent of occupied 

one- and two-family residential building basement fires 

(Table 7). The data presented in Table 7 are the raw counts 

from the NFIRS dataset and are not scaled to national estimates of AESs in basement fires.

Residential sprinkler systems help to reduce the risk of civilian and firefighter casualties, homeowner insurance premiums, and uninsured property losses. Yet many residences 

are unequipped with AESs that are often installed in hotels 

and businesses. Sprinklers are required by code in hotels 

and many multifamily residences. There are major movements in the U.S. fire service to require or facilitate use of 

sprinklers in all new homes, which could improve the use 

of residential sprinklers in the future. At present, however, 

they are largely absent in residences nationwide.21 

USFA and fire service officials across the nation are working to promote and advance residential fire sprinklers. More 

information on costs and benefits, performance, training bulletins, and public education and outreach materials regarding residential sprinklers is available at http://

www.usfa.fema.gov/prevention/technology/home_fire_

sprinklers.html. Additionally, USFA’s position statement on 

residential sprinklers is available at http://www.usfa.fema.

gov/about/sprinklers_position.html. 

Table 7. NFIRS Automatic Extinguishing System Data for Occupied One- and Two-Family 

Residential Building Basement Fires (2010-2012)

Automatic Extinguishing System Presence Count Percent

Automatic extinguishing system present 144 1.1

Partial system present 16 0.1

Automatic extinguishing system not present 11,655 93.0

Unknown 716 5.7

Total incidents 12,531 100.0

Source: NFIRS 5.0.

Notes: 1. The data presented in this table are raw data counts from the NFIRS dataset. They do not represent national estimates of AESs in basement fires in occupied one- and two-family residential buildings. They 

are presented for informational purposes. 

2. Total does not add up to 100 percent due to rounding.
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 9

Examples

The following are recent examples of basement fires 

reported by the media:

•	 October 2014: A basement fire was reported at 3:06 

a.m. in Morris, Minnesota. When firefighters arrived, 

they encountered heavy black smoke coming from the 

basement windows. A dehumidifier in the basement 

caused the fire, which had been burning for an extensive amount of time. It was reported that the home had 

working smoke alarms, which allowed the family of four 

and a pet dog to escape without injury.22 

•	 October 2014: A late night house fire in Birch Run 

Township, Michigan, started in a basement bedroom. 

Although the fire spread to another room, it was contained to the basement. Two residents escaped the fire 

uninjured; however, the house sustained heavy smoke 

damage. The cause of the blaze is unknown.23

•	 October 2014: A fire that originated in the basement 

of a Racine, Wisconsin, home was unusual in that it 

mostly self-extinguished due to the lack of available 

oxygen after spreading through much of the basement. 

No civilian or firefighter injuries were reported; however, the fire resulted in the loss of a pet cat and caused 

an estimated $75,000 in damages. The cause of the fire 

was reported to be an electrical connection that failed or 

overheated.24

•	 September 2014: A basement fire in a single-story home 

in Godfrey, Illinois, started in the basement laundry 

room. Firefighters were able to prevent the fire from 

spreading into the main floor of the home. Significant 

fire damage occurred in a large portion of the basement, along with heavy smoke damage throughout the 

house, resulting in an estimated $100,000 loss of property and contents. The cause of the fire remains under 

investigation.25

NFIRS Data Specifications for One- and 

Two-Family Residential Building Basement 

Fires

Data for this report were extracted from the NFIRS annual 

Public Data Release files for 2010, 2011 and 2012. Only 

Version 5.0 data were extracted. 

Basement fires were defined using the following criteria:

•	 Aid Types 3 (mutual aid given) and 4 (automatic aid 

given) were excluded to avoid double counting of 

incidents.

•	 Incident Types 111 to 123 (excluding Incident Type 112):

Incident 

Type Description

111 Building fire

113 Cooking fire, confined to container

114 Chimney or flue fire, confined to chimney or flue

115 Incinerator overload or malfunction, fire confined

116 Fuel burner/boiler malfunction, fire confined

117 Commercial compactor fire, confined to rubbish

118 Trash or rubbish fire, contained

120 Fire in mobile property used as a fixed structure, other

121 Fire in mobile home used as fixed residence

122 Fire in motor home, camper, recreational vehicle

123 Fire in portable building, fixed location

Note: Incident Types 113 to 118 do not specify if the structure is a building.

•	 Property Use 419: one- or two-family dwelling, 

detached, manufactured home, mobile home not in 

transit, duplex.

•	 Structure Type: 

– For Incident Types 113 to 118:

— 1—Enclosed building.

— 2—Fixed portable or mobile structure, and 

Structure Type not specified (null entry).

– For Incident Types 111 and 120 to 123:

— 1—Enclosed building.

— 2—Fixed portable or mobile structure.

•	 Story of Fire Origin: -1 or -2.

The analyses contained in this report reflect the current 

methodologies used by USFA. USFA is committed to providing the best and most currently available information on 

the U.S. fire problem and continually examines its data and 

methodology to fulfill this goal. Because of this commitment, data collection strategies and methodological changes 

are possible and do occur. As a result, analyses and estimates 

of the fire problem may change slightly over time. Previous 

analyses and estimates on specific issues (or similar issues) 

may have used different methodologies or data definitions 

and may not be directly comparable to the current ones.
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 10

Information regarding USFA’s national estimates for residential building fires as well as the data sources used to 

derive the estimates can be found in the document, “Data 

Sources and National Estimates Methodology Overview 

for the U.S. Fire Administration’s Topical Fire Report Series 

(Volume 15),” http://www.usfa.fema.gov/downloads/

pdf/statistics/data_sources_and_national_estimates_

methodology.pdf. This document also addresses the specific 

NFIRS data elements analyzed in the topical reports, as well 

as “unknown” data entries and missing data.

To request additional information or to comment on this 

report, visit http://www.usfa.fema.gov/contact.html.

Notes: 

1National estimates are based on 2010-2012 native Version 5.0 data from NFIRS, residential structure fire loss estimates 

from the National Fire Protection Association’s (NFPA’s) annual surveys of fire loss, and USFA’s residential building fire loss 

estimates: http://www.usfa.fema.gov/data/statistics/order_download_data.html. Further information on USFA’s residential 

building fire loss estimates can be found in the “National Estimates Methodology for Building Fires and Losses,” August 

2012, http://www.usfa.fema.gov/downloads/pdf/statistics/national_estimate_methodology.pdf. For information on NFPA’s 

survey methodology, see NFPA’s report on fire loss in the U.S.: http://www.nfpa.org/~/media/Files/Research/NFPA%20

reports/Overall%20Fire%20Statistics/osfireloss.pdf. In this topical report, fires are rounded to the nearest 100, deaths to the 

nearest five, injuries to the nearest 25, and dollar loss to the nearest million dollars. 

2In NFIRS Version 5.0, a structure is a constructed item of which a building is one type. In previous versions of NFIRS, the 

term “residential structure” commonly referred to buildings where people live. To coincide with this concept, the definition 

of a residential structure fire for NFIRS 5.0 has, therefore, changed to include only those fires where the NFIRS 5.0 Structure 

Type is 1 or 2 (enclosed building and fixed portable or mobile structure) with a residential property use. Such structures 

are referred to as “residential buildings” to distinguish these buildings from other structures on residential properties that 

may include fences, sheds and other uninhabitable structures. In addition, confined fire incidents that have a residential 

property use but do not have a Structure Type specified are presumed to occur in buildings. Nonconfined fire incidents that 

have a residential property use without a Structure Type specified are considered to be invalid incidents (Structure Type is a 

required field) and are not included.

3“One- and two-family residential buildings” include detached dwellings, manufactured homes, mobile homes not in transit, and duplexes.

4In NFIRS, basements are defined as Story of Fire Origin: -1 or -2. This information is collected for nonconfined fires, and it is 

only voluntary for confined fires. This may impact direct comparisons between basement fires and all residential building fires.

5USFA, “Fire Safety Checklist,” usfa.fema.gov, FA-285, April 2012, http://www.usfa.fema.gov/downloads/pdf/publications/

fa_285.pdf (accessed Oct. 14, 2014).

6Jerrard, Jane, “UL Basement Fire Study,” firefighternation.com, June 14, 2012, http://www.firefighternation.com/article/

firefighter-safety/ul-basement-fire-study (accessed Oct. 10, 2014).

7Fire department participation in NFIRS is voluntary; however, some states do require their departments to participate in the 

state system. Additionally, if a fire department is a recipient of a Fire Act Grant, participation is required. From 2010 to 2012, 

70 percent of NFPA’s annual average estimated 1,365,300 fires to which fire departments responded were captured in NFIRS. 

Thus, NFIRS is not representative of all fire incidents in the U.S. and is not a “complete” census of fire incidents. Although 

NFIRS does not represent 100 percent of the incidents reported to fire departments each year, the enormous dataset exhibits 

stability from one year to the next, without radical changes. Results based on the full dataset are generally similar to those 

based on part of the data.

8In NFIRS, confined fires are defined by Incident Type codes 113-118.

9NFIRS distinguishes between “content” and “property” loss. Content loss includes losses to the contents of a structure due 

to damage by fire, smoke, water and overhaul. Property loss includes losses to the structure itself or to the property itself. 

Total loss is the sum of the content loss and the property loss. For confined fires, the expectation is that the fire did not 

spread beyond the container (or rubbish for Incident Type code 118), and hence, there was no property damage (damage to 

the structure itself) from the flames. However, there could be property damage as a result of smoke, water and overhaul.
TFRS Volume 15, Issue 10/One- and Two-Family Residential Building Basement Fires (2010-2012) Page 11

10The average fire death and fire injury loss rates computed from the national estimates do not agree with average fire 

death and fire injury loss rates computed from NFIRS data alone. The fire death rate computed from national estimates is 

(1,000*(65/6,500)) = 10.0 deaths per 1,000 one- and two-family residential building basement fires, and the fire injury rate 

is (1,000*(400/6,500) = 61.5 injuries per 1,000 one- and two-family residential building basement fires.

11For the purposes of this report, the time of the fire alarm is used as an approximation for the general time at which the 

fire started. However, in NFIRS, it is the time at which the fire was reported to the fire department.

12Source: NFIRS.

13The USFA Structure Fire Cause Methodology was used to determine the cause of one- and two-family residential building 

basement fires. The cause methodology and definitions can be found in the document “National Fire Incident Reporting 

System Version 5.0 Fire Data Analysis Guidelines and Issues,” July 2011, http://www.usfa.fema.gov/downloads/pdf/nfirs/

nfirs_data_analysis_guidelines_issues.pdf.

14Fires caused by intentional actions include, but are not limited to, fires that are deemed to be arson. Intentional fires are 

those fires that are deliberately set and include fires that result from the deliberate misuse of a heat source and fires of an 

incendiary nature (arson) that require fire service intervention. For information and statistics on arson fires only, refer to the 

Uniform Crime Reporting Program arson statistics from the U.S. Department of Justice, FBI, Criminal Justice Information 

Services Division, http://www.fbi.gov/about-us/cjis/ucr/ucr.

15Total percent of one- and two-family residential building fires does not add to 100 percent due to rounding.

16“One- and Two-Family Residential Building Fires (2010-2012),” Topical Fire Report Series, USFA, September 2014, 

Volume 15, Issue 3, http://www.usfa.fema.gov/downloads/pdf/statistics/v15i3.pdf.

17Total does not add up to 59 percent due to rounding.

18Source: NFIRS.

19Total does not add up to 15 percent due to rounding.

20Greene, Michael and Craig Andres, “2004-2005 National Sample Survey of Unreported Residential Fires,” Division of 

Hazard Analysis, Directorate for Epidemiology, U.S. Consumer Product Safety Commission, July 2009.

21U.S. Department of Housing and Urban Development and U.S. Census Bureau, 2011 American Housing Survey, “Health 

and Safety Characteristics-All Occupied Units (National),” Table S-01-AO, http://factfinder2.census.gov/faces/tableservices/

jsf/pages/productview.xhtml?pid=AHS_2011_S01AO&prodType=table.

22“Three fire departments called to early morning blaze in Morris,” morrissuntribune.com, Oct. 6, 2014, http://www.

morrissuntribune.com/content/three-fire-departments-called-early-morning-blaze-morris (accessed Oct. 9, 2014).

23Jordan, Heather, “Fire officials investigate Birch Run house fire that started in basement bedroom,” mlive.com, Oct. 5, 

2014, http://www.mlive.com/news/saginaw/index.ssf/2014/10/fire_officials_investigate_bir.html (accessed Oct. 9, 2014).

24“House fire causes $75,000 damage,” journaltimes.com, Oct. 5, 2014, http://journaltimes.com/news/local/house-firecauses-damage/article_8d22cb5d-d8d6-5dc2-bf4d-81e6f3693937.html (accessed Oct. 9, 2014).

25“Basement fire displaces Godfrey family,” thetelegraph.com, Sept. 8, 2014, http://thetelegraph.com/news/news/50277807/

Basement-fire-displaces-Godfrey-family (accessed Oct. 9, 2014).