For example, for the Gases under pressure hazard class, the hazard categories are Compressed gas, Liquefied gas, Refrigerated liquefied gas and Dissolved gas. These classes relate to the physical state of the gas when packaged and do not describe the degree of hazard.
1 In 1596, a flush toilet was invented and built for Queen Elizabeth I by her Godson, Sir John Harrington. 2  The first patent for the flushing toilet was issued to Alexander Cummings in 1775. 3  During the 1800s, people realized that poor sanitary conditions caused diseases.
The Thor washing machine was the first electric clothes washer sold commercially in the United States. Produced by the Chicago-based Hurley Electric Laundry Equipment Company, the 1907 Thor is believed to be the first electrically powered washer ever manufactured, crediting Hurley as the inventor of the first automatic washing machine.