They were commonplace in the 18th century when black powder use was at its height. As gunpowder is highly flammable, strict measures were undertaken to prevent fatal accidents. A single spark could set off an explosive chain reaction, and individuals who worked with magazines were required to only use wooden and copper tools, wear shoes without nails, and always ensure that they were not carrying stray matches. In some cases, these workers were even mandated to wear clothes without pockets to eliminate the latter risk entirely.
Although gunpowder magazines were generally erected in open, secluded areas like the Boston Common during the American Revolutionary War, an exception had to be made when it came to military fortifications because soldiers needed gunpowder close at hand. Magazines built within forts therefore were designed in such a way that, should they explode, buildings surrounding it would collapse on the ensuing fire and smother it.