In 2025, fire departments serving Chelmsford responded to 150 fire and hazmat incidents — from cooking fires to gas leaks to a single $182K building blaze. Here's the full picture.
Gas leak (natural gas or LPG) lead by count. Building fires lead by dollars. Together the top five categories make up about 55% of all calls.
Nov peaks. Dec dips. Watch for the typical fall climb starting in October.
275 incidents 2021–2025. Peak year was 2025. $2.2M cumulative property loss. 1 civilian deaths.
| Year | Incidents | YoY | |
|---|---|---|---|
| 2021* | 14 | — | |
| 2022* | 18 | — | |
| 2023* | 21 | — | |
| 2024 | 72 | — | |
| 2025 | 150 | +108.3% |
* Well below Chelmsford's usual volume. That almost always means one or more departments didn't submit a full year to NFIRS, not that fires dropped, so no year-over-year change is shown for it.
For the 14 building fires Chelmsford departments responded to in 2025, here's how they were classified once investigators were finished.
NFIRS Area of Origin (AREA_ORIG) for the 144 building fires investigators classified across 2021–2025. The room or location where ignition occurred — kitchens, bedrooms, exterior, vehicle areas — tells you where to focus prevention.
| # | Area of origin | Count | Share | |
|---|---|---|---|---|
| 1 | Engine area, running gear, wheel area | 38 | 26.4% | |
| 2 | Cooking area, kitchen | 15 | 10.4% | |
| 3 | Outside area, other | 12 | 8.3% | |
| 4 | Undetermined | 8 | 5.6% | |
| 5 | Highway, parking lot, street: on or near | 7 | 4.9% | |
| 6 | Wildland, woods | 6 | 4.2% | |
| 7 | Cargo/trunk area - all vehicles | 5 | 3.5% | |
| 8 | Open area - outside; included are farmland, field | 5 | 3.5% | |
| 9 | Vehicle area, other | 4 | 2.8% | |
| 10 | Exterior, exposed surface | 4 | 2.8% | |
| 11 | All other areas | 40 | 27.8% |
NFIRS Heat Source (HEAT_SOURC) — the physical thing that started it. Spark or ember from operating equipment, an open flame, smoking materials, or hot embers from a fireplace are the leading culprits nationwide. Here's the Chelmsford mix.
| # | Heat source | Count | Share | |
|---|---|---|---|---|
| 1 | Undetermined | 52 | 36.1% | |
| 2 | Radiated, conducted heat from operating equipment | 28 | 19.4% | |
| 3 | Heat from powered equipment, other | 11 | 7.6% | |
| 4 | Spark, ember or flame from operating equipment | 9 | 6.2% | |
| 5 | Arcing | 9 | 6.2% | |
| 6 | Heat from direct flame, convection currents | 5 | 3.5% | |
| 7 | Hot ember or ash | 4 | 2.8% | |
| 8 | Cigarette | 4 | 2.8% | |
| 9 | Radiated heat from another fire | 4 | 2.8% | |
| 10 | Heat source: other | 3 | 2.1% | |
| 11 | All other sources | 15 | 10.4% |
Largest single-incident property losses reported by Chelmsford departments in 2025. These 8 fires alone account for 83% of the city's annual total.
| # | Property loss | Type | Severity | Status |
|---|---|---|---|---|
| 1 | $181,708 | Building fires | Significant | Investigated |
| 2 | $100,000 | Building fires | Significant | Investigated |
| 3 | $89,000 | Building fires | Significant | Investigated |
| 4 | $75,000 | Building fires | Significant | Investigated |
| 5 | $30,000 | Building fires | Significant | Investigated |
| 6 | $25,000 | Building fires | Significant | Investigated |
| 7 | $23,376 | Passenger vehicle fire | Significant | Investigated |
| 8 | $20,000 | Passenger vehicle fire | Significant | Investigated |
Per-capita rates let us compare apples to apples. Chelmsford sits below the national average for incidents per resident.
9 fire-related casualties recorded in NFIRS Module 11 across the 2021–2025 window. Age, gender, and severity are coarse-binned — no individual identification possible.
| Age | Count | |
|---|---|---|
| 0-9 | 0 | |
| 10-19 | 0 | |
| 20-29 | 0 | |
| 30-39 | 2 | |
| 40-49 | 4 | |
| 50-59 | 2 | |
| 60-69 | 0 | |
| 70-79 | 0 | |
| 80+ | 1 |
Top 25 wildfires (1992+) in the FPA-FOD ignitions database, scaled by acres. 3,987 acres burned in this 50-mile radius. Each dot is a fire — bigger dots burned more land.
| Year | Cause | Acres | Distance | |
|---|---|---|---|---|
| 2005 | Missing data/not specified/undetermined | 800 | 15.8 mi | |
| 2008 | Missing data/not specified/undetermined | 700 | 15.8 mi | |
| 2003 | Missing data/not specified/undetermined | 300 | 23.9 mi | |
| 2002 | Missing data/not specified/undetermined | 300 | 15.8 mi | |
| 2014 | Missing data/not specified/undetermined | 256 | 15.9 mi | |
| 2015 | Missing data/not specified/undetermined | 250 | 16.0 mi | |
| 2016 | Arson/incendiarism | 190 | 48.1 mi | |
| 2007 | Missing data/not specified/undetermined | 186 | 17.5 mi | |
| 2016 | Missing data/not specified/undetermined | 172 | 15.7 mi | |
| 2004 | Missing data/not specified/undetermined | 120 | 43.1 mi | |
| 2014 | Missing data/not specified/undetermined | 90 | 22.3 mi | |
| 2020 | Missing data/not specified/undetermined | 79 | 16.0 mi |
Top 2 ZIP codes by NFIRS incident count across 2021–2025. Each ZIP has its own fire profile — dive in for neighborhood-level context.
Six Massachusetts cities with population within ±25% of Chelmsford. Useful comparison targets — same state, similar size, different fire profile.
A 30-minute weekend can cut your home's exposure substantially. These four checklists are a good starting point.
Numbers reflect incidents reported by participating fire departments to the National Fire Incident Reporting System (NFIRS) Public Data Release for calendar year 2025. NFIRS is voluntary — about 23,000 of roughly 30,000 US fire departments report — so totals are a strong indicator, not a complete census. Per-capita comparisons use 2023 ACS population estimates. Wildland fire data complements NFIRS with NIFC and USFS perimeters. Active-fire counts come from a dated NIFC snapshot, not a live feed.