On Sept. 19, 1941, a truck carrying 500 quarts of nitroglycerin, 300 quarts of glycerine and four 25-pound cases of dynamite exploded with tremendous force on the top of Marshburg hill, about 10 miles southwest of Bradford. The explosion killed two men and another, Clarendon Streeter, was left permanently blinded in his right eye. The truck driver, John Gloss, was vaporized by the blast, and his body never recovered.

It had long been recognized that transporting nitroglycerin was dangerous and explosions were common throughout the history of the oil fields. Nitroglycerin is an oily, colorless liquid explosive so unstable that the slightest jolt, impact or friction can cause it to spontaneously detonate. It is considered one of the world’s most powerful explosives.

At the peak of Bradford’s oil boom, however, it was invaluable to the oil industry. In the early days of oil drilling, gunpowder was the primary method used to “shoot” wells but this technique was soon surpassed by the invention of the Roberts Torpedo in 1865 by Union Army Col. Edward Roberts and his brother Walter. To stimulate oil production, the “shooters” would carefully lower a torpedo filled with liquid nitroglycerin to the bottom of the well using specialized equipment. Once detonated, the shock wave fractured the oil-bearing rock, creating fissures that allowed trapped oil to flow more freely to the surface.

The nitro had to be brought to the well head from a nearby explosive storage magazine, and it took a brave man to willingly drive a team of horses over rough terrain, with a load of nitroglycerin in the back of the wagon.

Scores of men were killed during those early years. Nitroglycerin is extremely sensitive to exploding and a jolt in the wagon, a bump in the road, one careless moment handling a nitro can or almost any adverse conditions would send the men, horses, wagons, buildings and anything surrounding it, into infinity. Usually, nothing was ever recovered, except for an occasional body part.

Bradford’s history also contains many stories concerning nitroglycerin explosions in storage magazines. On March 10, 1885, for example, the magazine and factory of the Rock Glycerin Co., just half a mile from Custer City and 3.5 miles from Bradford, blew up with such force that twin jets of flame and smoke shot 300 feet in the air, knocked dishes from the shelves in Lewis Run, demolished all the telegraph lines along the railroad track, crushed a 600-gallon water tank like an eggshell, and created a hole 20 feet deep and 30 feet wide. More than 6,000 pounds of nitroglycerin had let loose.

In December 1899 a red brick magazine belonging to the Pennsylvania Torpedo Co., located up Bolivar Run just a half mile from the back road to Limestone, and containing 300 quarts of glycerin, blew up at 5:40 a.m. when an oil stove malfunctioned and set off the disastrous chain of events.

It was one of the loudest explosions ever heard in Bradford. Windows were shattered, dishes cracked, clocks knocked off their shelves, several chimneys toppled, the windows at the National Transit buildings and the Wood Rim Co. were broken, houses were rocked and jarred, and the sound was heard as far away as Knapp Creek, Salamanca and Ellicottville, N.Y. It was so loud and bright that a man on Mechanic Street thought Bradford had been hit by a meteorite.

People were roused from bed, woken by the boom. The Bradford Era wrote “Having felt many like explosions in the past, Bradford people at once guessed the true cause of the commotion. It was a glycerin blow up. There is a peculiar, stunning, jarring force connected with exploding glycerin which other compounds do not seem to possess. It strikes harder than other concussions. It causes the earth to rock and tremble and the detonation sweeps in a sharp, reverberating volume of sound, far and wide.”

An interview with an “old oil operator” in the Bradford oil regions published in Scientific American magazine (Volume 55, Dec. 11, 1886) described just how dangerous nitroglycerin could be. “Besides human bodies, the iron frames of wagons, and even the ponderous nitroglycerin safes, all have been removed from human vision by an explosion as effectually as if they had never been formed, and the mystery of their utter annihilation cannot be explained.”

On June 24, 1893, an article in The Bradford Era described such an accident on the road from Big Shanty to Guffy. “Yesterday morning Andy Muldoon, the well shooter, was a living, breathing human being. At seven o’clock there was no Andy Muldoon; he had been annihilated – blown out of existence.”

Considered an experienced shooter and a careful one, he unfortunately had a reputation for driving the horses too fast. It was supposed that speed and poor road conditions were the cause of the explosion. The 120 quarts of nitroglycerin he was carrying blew Andy, the wagon, and horses into eternity. Pieces of flesh were discovered at the scene but all were too small, making it impossible to distinguish the difference between what remained of Andy and what remained of the team of horses that had been pulling the wagon. All that could be found was scraped off the ground and gathered from the trees. Roughly 12 pounds of man and horse were gathered into a box and buried at St. Bernard’s cemetery the next day.

Still, despite the well-known dangers of transporting nitroglycerin, the city of Bradford permitted explosives of all kinds to pass through its streets for nearly 50 years.

A near disaster on Aug. 11, 1922, changed everyone’s opinion when a Pringle Co. nitroglycerin truck collided with a Miles-Bradford truck at the corner of East Main Street and Kendall Avenue. Amazingly, the nitro did not explode, although the Miles-Bradford truck hit the nitroglycerin truck with enough force to bend its axle.

The Era later reported “it is the greatest wonder in the world that the glycerin did not blow up and make a hole in East Bradford that the St. James hotel could have been placed in. Only the characteristic eccentricities of the nitro saved the principals and bystanders from a horrible death.”

The close call served as a stark reminder of the potential devastation such accidents could cause, prompting the city to reconsider its policies on allowing explosives to pass through its streets.

Two weeks later, a meeting was held with representatives from powder companies, railroads, and city officials. Various options were discussed, including restricting nitroglycerin shipments to nighttime hours when streets were less crowded, or banning them from the city altogether. After extensive debate from all sides, a new ordinance was drawn up, mandating a police escort for every shipment of nitroglycerin as it passed through the city to the city limits.

A police escort could not always guarantee safety, however. Just two years later, on June 3, 1924, a 21-year-old man named Harold Howard was “blown to fragments” near what is now the Pitt-Bradford campus on West Corydon Street, only 300 yards from Dorothy Lane. The explosion, attributed to faulty packaging and a leaking can of explosives, scattered debris from both Howard’s body and the truck over a 100-yard radius, leaving a massive crater in the road. Officer Charles Hipchen, who narrowly escaped the blast, had accompanied the “death car through the city on his patrol” turning back just moments before the detonation occurred.

Less than 20 years later, in September 1941, many longtime residents of Bradford recall one of the most memorable nitroglycerin accidents, which took place on Marshburg Hill.

There was no premonition of the disaster that loomed ahead that day. It was a clear autumn day and driving conditions were excellent. An American Glycerin truck, driven by John Gloss of Irvine Mills, N.Y., was enroute from Limestone, N.Y., to the Warren area with a full load of nitroglycerin for a magazine in that area. Gloss had loaded the truck at Limestone that morning then set off to make his deliveries, driving a somewhat rambling route through Foster Brook, Duke Center, Summit, Rew, Minard Run and Custer City, then up Route 770 toward Marshburg. The truck passed through Custer City about 10:15 a.m.

Also on the road that day were Clarendon Streeter, 45, a prominent local oil producer, and J. Clifford Martin, 46, executive secretary of the Bradford District Pennsylvania Grade Crude Oil Producers’ association, on their way to a meeting in Oil City.

What happened next remains a mystery, but it is believed that Streeter had decided to pass the slower-moving truck and for some reason the nitroglycerin in the truck exploded, killing both the truck’s driver, Gloss; and Martin, the passenger in the front seat of Streeter’s automobile; and seriously wounding Streeter.

The Bradford Era reported: “The blast blew the truck to bits, shattered the automobile, ripped out a hole 18 feet wide, 10 feet in length and 4 feet deep in the asphalt, and leveled trees for 100 yards along the highway. The force of the terrific explosion was in evidence at the scene where the Streeter car, a large sedan, was blown to a spot 30 yards west of the crater in the road, the direction the two vehicles were headed. The concussion shattered the windows and pushed in the sides and tops of the car. The truck was almost completely destroyed. The largest single piece of the truck was the motor found lying in a ditch on the left side of the road about 100 yards west of the crater.”

An investigation by the Pennsylvania State Motor Police began immediately but the official inquest report, completed within the week, stated that no known factor caused the explosion.

This was the last memorable accidental nitroglycerin explosion in recent times, a reminder of the power of the world’s strongest explosive.