Remembering The Picatinny Arsenal Disaster 99 Years Later

MORRIS COUNTY, NJ — This week marks the 99th anniversary of the Picatinny Arsenal explosion, a freak accident that killed 19 people, injured dozens more, and destroyed millions of dollars worth of military equipment.

Picatinny Arsenal, still active today, is located in Jefferson and Rockaway Townships and consists of more than 6,000 acres. Originally established in 1880, the arsenal has served as a military hub ever since.

On the arsenal was the Lake Denmark Naval Ammunition Depot (NAD), which consisted of several munitions storage buildings. According to an article from Rutgers University, many U.S. ammo depots were overstocked following World War I, including the Lake Denmark NAD.

This excessive storage set the stage for the 1926 Lake Denmark NAD explosion, a turning point in 20th-century ammunition storage practices.

At around 5:15 p.m. on July 10, 1926, the Lake Denmark Naval Ammunition Depot (NAD) was struck by lightning during a storm, detonating the ammunition it stored. The explosions carried on for two to three days, destroying 187 of the 200 buildings at the arsenal, according to historians.

The explosions caused a “complete and total annihilation of structures within a radius of 2,700 feet and damaged buildings up to 8,700 feet away,” according to a Picatinny Arsenal statement.

It is thought that the first explosion was so powerful that it had stopped the tower clock at the First Methodist Episcopal Church in Rockaway Borough, and even shook the ground and shattered glass in the central business district, according to historians.

According to Picatinny experts, most of the 19 who died were U.S. Marines attempting to quell the fires. Another 50 people were injured, and approximately $40 million worth of damage was dealt, equivalent to more than $700 million today.

How The Disaster Served As A Catalyst For Change

Following the explosion, the arsenal wasn’t the only thing in need of rebuilding. Officials determined that new ammo storage protocols needed to be put in place to make sure something like this never happened again.

According to the Rutgers report, NAD buildings at the time of the incident held an excess of 1,600,000 pounds of TNT stored in a single building.

Following a study of the disaster, the American Table of Distances announced that munition storage buildings can “no longer exceed 300,000 pounds of explosive material in any storage facility and any inhabited building must be a minimum of 2,275 feet away, regardless if the storage structure is barricaded or unbarricaded.”

Additionally, the architectural standards of munition storage buildings had changed, calling for “the adoption of the earth-covered, arched, concrete igloo(s)” for increased fire and blast protection.

Picatinny Arsenal cleaned up the aftermath of the disaster and proceeded with “substantial construction” less than ten years later, strictly adhering to the newly updated protocols.

The arsenal and the NAD would continue to serve as a vital site throughout the 20th Century, acting as an ammo depot and research facility throughout World War II and into the Cold War.

Today, the Picatinny Arsenal serves as the U.S. Army's Joint Center of Excellence for Guns and Ammunition. The entity serves as a research and development center for advanced weaponry for all U.S. military branches.

A memorial was put in place near the former Marine barracks, where it can be seen today, serving as “a stark reminder of the events that happened that fateful day.”