End of Watch October 27, 2018
Age 65
Tour of Duty 31 yrs
The Vigil Panel 169 ›
Gender Male

Incident

Location: New York Incident Date: Tuesday, September 11, 2001 Weapon: Aircraft; Passenger jet Offender: 19 suicide attackers

Special Agent Dennis McCarthy died as the result of cancer contracted due to his exposure to toxic substances following the 9/11 Terrorist Attacks at the World Trade Center in New York City, New York.

Agent McCarthy responded to help secure the site of the destroyed U.S. Custom House at the World Trade Center site in the immediate aftermath of the attacks. He remained at the scene to assist with search and recovery efforts.

Special Agent McCarthy had served with Homeland Security Investigations and the former United States Customs Service for over 31 years. Special Agent McCarthy's brother was also a DEA agent who was killed in combat during the Gulf War while activated with the U.S. Marine Corps Reserve.

September 11, 2001 - The Years After

Special Agent Dennis Patrick McCarthy was assigned to the search and recovery at the World Trade Center site after September 11, 2001. He was 48 years old that fall.

He died on October 27, 2018 - 17 years and 1 month later - of an illness contracted there. He was 65.

He is one of 599 officers honored here, and one of 7 at United States Department of Homeland Security - Immigration and Customs Enforcement - Homeland Security Investigations.

The most recent of these deaths was October 24, 2025.

Officers who worked the search, rescue, and recovery at the World Trade Center site breathed contaminated air for weeks and months afterward. Many developed cancers and respiratory disease, and they have gone on dying of it ever since.

Seventy-two officers were killed on the morning itself. Hundreds more have died in the years that followed. They are honored here together, because the same attack killed them all. With some it simply took longer.

In Our Keeping

Permanent identifier
BO-US-FED-FB31985A
Stewardship
Maintained by NeuraWeb Global Inc.
Added to badge.nw
April 2, 2026
Last updated
July 23, 2026

Honored here by 1 sentinel - 1 tribute.

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Tributes

You walked into it and it took years to finish the job.
Special Agent McCarthy gave the United States Department of Homeland Security 31 years.
Thank you for your service. Gone but never to be forgotten.
Rest easy, Special Agent McCarthy.

— S. Vincent Anthony, U.S. Army 1985-1993

Agency

Location Washington, DC
Platform Identity usdhsicehsifed.fed.us.gov.nw

Service Record

End of Watch October 27, 2018
Tour of Duty 31 yrs
Age 65
Gender Male

Incident Details

Cause Illness
Cause Detail 9/11 related illness
Weapon Aircraft; Passenger jet
Offender 19 suicide attackers

Special Agent Dennis Patrick McCarthy is one of 2,974 officers lost to illness connected to their service across the full record of this memorial — 9.1% of all 32,508 officers honored here.

In DC, 137 of 1,419 officers were lost to illness connected to their service — 9.7% of this state's fallen. That is 0.6 percentage points above the national rate of 9.1%.

At United States Department of Homeland Security - Immigration and Customs Enforcement - Homeland Security Investigations, 8 of 10 officers on record were lost to illness connected to their service — 80% of this agency's fallen.

United States Department of Homeland Security - Immigration and Customs Enforcement - Homeland Security Investigations
8
of 10 officers
80% Illness
DC — Statewide
137
of 1,419 officers
9.7% Illness
Nationwide
2,974
of 32,508 officers
9.1% Illness

National Cause Distribution

How Illness compares to all causes of officer death in the memorial record. Dennis Patrick McCarthy's cause is highlighted.

Felonious
17,623 (54.2%)
Accident
10,088 (31%)
Illness
2,974 (9.1%)
Cardiac
1,306 (4%)
Undetermined
260 (0.8%)
Suicide
256 (0.8%)
vehicular
1 (0%)

How Dennis Patrick McCarthy Compares

Age at End of Watch
65
This officer
Avg for Illness: 47.8 years
Years of Service
31
This officer
Avg for Illness: 18.9 years

Offender Outcome

19 suicide attackers

When Illness Deaths Occur

Monthly distribution of Illness deaths across the full memorial record. Dennis Patrick McCarthy is highlighted in Oct.

Jan
294
Feb
198
Mar
185
Apr
226
May
201
Jun
181
Jul
217
Aug
281
Sep
291
Oct
376
Nov
239
Dec
285

Incident Location