A boiler suit (also known as coveralls) is a loose-fitting, one-piece protective garment that covers the entire body except for the head, hands, and feet. Originally designed for miners and maintenance workers cleaning coal-fired boilers, it prevents soot, grease, and debris from seeping through gaps while providing reinforced coverage with no loose jacket tails to catch in machinery. Modern boiler suits are widely used across manufacturing, heavy engineering, and the food industry, while also inspiring streetwear utility fashion.