Unexploded WWII Bombs Have Grown More Dangerous Over Time

An unexploded WWII-era bomb found in the Solomon Islands.

An unexploded WWII-era bomb found in the Solomon Islands. New Zealand Defence Force

Long-buried bombs leftover from World War I and World War II have become more volatile, a new study finds, raising the odds that a dormant explosive detonates.

During those wars, bombs sometimes lodged in the ground or sunk to the bottom of the sea, but did not explode. Leftover bombs are still occasionally unearthed in a back garden, found washed up on a beach, or caught in fishing net. Officials are typically able to isolate these bombs and detonate them in a secluded place — though not always. Occasionally an excavator will strike a dormant bomb at a construction site, with deadly results.

Now, the changing chemistry of unexploded bombs may be making them more dangerous, according to a new study in Royal Society Open Science. The research notes that bombs from the early 20th century were usually made with Amatol, a mix of ammonium nitrate and TNT, and that Amatol grows more volatile when exposed to iron or other metals found in soil. For the research, two bomb specialists in Norway analyzed samples of Amatol from battle sites across Europe, finding that explosives made with the material are “generally much more sensitive to impact than previously assumed.”

Unexploded bombs can leak harmful chemicals into soil and water, and when detonated, can cause havoc. The study calls for taking extra precautions when undertaking new construction on old battlegrounds.


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