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.
Raritan Engineering Company, Inc. was founded in 1958 on the basis of the Patent for the PH Marine Toilet. 1  Its successor, the PHII is still manufactured by Raritan. The Crown Head, the worldâs first macerating Marine Toilet followed in 1966. The first small on-board waste treatment system came in 1974.