Where Nitroglycerin is Made

The inherent danger in explosive making can not be overstated; nitroglycerin - the explosive agent in dynamite - is extremely unstable at high temperatures and highly sensitive to physical shock. The elevated and almost constant risk of explosion prompted Atlas to put into effect a very rigorous set of safety protocols and precautions. The most evident of these precautions is simply space, lots and lots of space. The area that we had previously explored (the warehouses, power plant, and office) were known as the “Safety Side” and were set far from the part of the plant where the dynamite was made. Furthermore, each stage of the dynamite production process was also separated by a great deal of space as well. In the end, the entire production line stretched a good half mile in length. This ensured that if there was an accident in one building, it wouldn’t effect any other buildings in the line.

The first step in that process is the creation of the explosive agent itself - the nitroglycerin. This was done at the NG House, which sat deep in the woods far outside the safety side. This was by far the most dangerous step in the process, since each subsequent step further stabilized the nitro until it became relatively safe to handle within the dynamite sticks themselves. At the NG House, however, several things could go horribly wrong.

Here is an old photo of one of the plant’s NG Houses. Atlas had two NG houses, as well as every other building in its production line. This insured that if an accident happened at any one building, the entire production line wouldn’t have to shut down. At Atlas this turned out to be good policy, as the plant’s second NG House blew up some time in the 50’s. The building here then became the plant’s sole nitro producer for its remaining years. In this photo the building is being razed as part of the plant’s clean-up procedure. After the sensitive equipment was removed, the remains were burned in order to destroy any residual nitro. (in open air, nitro is much more stable and can be burned off without danger)

Today the only thing that remains from the old building is its massive concrete foundation and the burned remains of wood retaining walls. In yet another safety precaution, each building at Senter was encased on three sides in large earth berms, which these wood retaining walls are holding back. These berms insured that if an explosion did occur, the force of the blast would be directed through the non-bermed side of the building - out away from any other structure. Take a look at the BIG PICTURE to see the ruins in all their glory.

Here’s a look inside the building as it once was, as seen during the building’s dismantling. The NG House is four stories in height, with three of those stories sitting behind large earth berms. The production process starts at the top of the building, where the three components of Nitroglycerin are mixed in what is called a “nitro reactor”. First a pre-mixed solution of Nitric and Sulfuric acid are pumped into the “reactor”, followed by the glycerine in very steady and gradual amounts. During this process, the temperature of the solution must be kept below 20 degrees Celsius at all times. Any hotter then that will result in the creation of a very toxic gas. In order to keep that from happening, a large vat of cold water is kept under the reactor where the mixture could be dumped to kill the process if anything goes wrong.

From the there the nitro/acid mix is sent into a large settling tank, where its mixed with an equal amount of water and stirred with compressed air. After some time the spent acids float to the top of the tank and are discharged. The resulting nitro is then emptied from the settling tank and sent on to a water rinse before leaving the building. The entire process would take about an hour for a single batch of nitro.

Climbing up atop the earth bern surrounding the building, we found ourselves standing on the building’s third floor. This is where the nitro reactor would of sat. Along the walls we could make out two large circular openings, which were probably used to bring into the building the acid mix and glycerine from nearby storage tanks. There was nothing remaining of the reactor itself or the water bath. Just a concrete floor covered in leaves and debris.

Sitting down in the buildings “basement” - which in actuality is the first floor - is a large concrete pedestal that you see here. This would of supported the large settling tank, which as been removed. The top of the pedestal is slightly angled to help drain the NG from the tank. In front of the pedestal is a short concrete wall that forms a large box on the floor. I’m not sure what it was for, but it could of been another water bath in case the nitro had to be dumped.

After the nitro went through a water rinse, it would then be sent out of the NG house through this concrete tunnel. Here we’re looking back into the NG house from outside the earth berm. The nitro would flow by gravity alone along a rubber and lead lined “trough” out of the tunnel and down the hill to the next step in the production process.

Here’s a closer look inside the tunnel, showing a line of iron bolts in the walls. These were probably used to support the wood trough.

Once outside, the wood trough would rise along a line of wood posts, which you can see above. Though the trough is long gone, these wood posts still remain and form a long line through the woods for hundreds of feet before meeting up with the next building in the production process - the neutralizer house.

Thanks to Bill Haller for providing from his collection these great archive photos of the plant during demolition, photographed by Ted Sved.

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