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Special Agent

Mark C. Johnston

United States Department of Justice - Federal Bureau of Investigation — Washington, DC

September 11, 2001 → Illness

End of Watch September 12, 2017

Age 65

Tour of Duty 38 yrs

The Vigil Panel 373 · Column 1 · Line 3 ›

Gender Male

Incident Media Service The Sacrifice Memorials 1 Also Remembered Department 88

Incident

Special Agent Mark Johnston died as the result of cancer that he developed following his assignment to the search and recovery efforts at the World Trade Center site following the 9/11 Terrorist Attacks.

Special Agent Johnston had served with the FBI for 24 years and was assigned to the Atlantic City Resident Agency. He had served in law enforcement for a total of 38 years.

September 11, 2001 - The Years After

Special Agent Mark C. Johnston was assigned to the search and recovery at the World Trade Center site after September 11, 2001. He was 50 years old that fall.

He died on September 12, 2017 - 15 years and 11 months later - of an illness contracted there. He was 65.

He is one of 600 officers honored here, and one of 19 at United States Department of Justice - Federal Bureau of Investigation.

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

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Stewardship: Maintained by NeuraWeb Global Inc.
Added to badge.nw: August 2, 2026
Last updated: September 26, 2026

Honored here by 1 tribute.

Are you family? This record can be claimed and maintained by those who knew Mark. Claim this record.

Also honored at requiem.nw. One record, 2 gates. Mark is one person.

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Tributes

You walked into it and it took years to finish the job.
Special Agent Johnston gave 38 years.
Thank you for your service. Gone but never to be forgotten.
Rest easy, Special Agent Johnston.

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

Agency

Department United States Department of Justice - Federal Bureau of Investigation

Type Federal Agency

Location Washington, DC

Platform Identity usdjfbifed.fed.us.gov.nw

Service Record

End of Watch September 12, 2017

Tour of Duty 38 yrs

Age 65

Gender Male

Incident Details

Cause Illness

Cause Detail 9/11 related illness

Weapon Aircraft; Passenger jet

The Sacrifice · Illness

Mark is one of 2,028 officers lost to illness in the United States, 7.4% of the 27,552 remembered there.

34,103 officers are remembered on this memorial. Each number below is one of them.

Compare against

Time

In 2017, 52 officers in the United States were lost to illness, the 8th heaviest of 108 years on record. The heaviest was 2021, with 564.

Every year on record · United States

Who

Mark was 65. Of the 1,996 lost to illness in the United States whose age is recorded, half were between 42 and 58; the middle age was 51. Mark had served 38 years; the middle length of service was 20 years.

Age at death

Where he stood among them

Age by years of service

III

When

September holds 11.2% of these deaths in the United States; October holds the most, 14.9%. Tuesdays: 13.3%.

By month

By day of the week

How

Illness deaths account for 7.4% of all 27,552 deaths in the United States, the 3rd most common cause. The weapon recorded was aircraft; passenger jet, in 29.5% of these deaths.

Every cause

Weapons recorded