Exxon Valdez oil spill cleanup, 2-butoxyethanol, was identified as "one of the agents that caused liver, kidney, lung, nervous system, and blood disorders among cleanup crews in Alaska following the 1989 "Exxon Valdez" spill. Mechanical cleanup was started shortly afterwards using booms and skimmers, but the skimmers were not readily available during the first 24 hours following the spill, and thick oil and kelp tended to clog the equipment. Despite civilian insistence for a complete clean, only 10% of total oil was actually completely cleaned. Exxon was widely criticized for its slow response to cleaning up the disaster and John Devens, the mayor of
Oil tanker instrument, Shell consulted the "London Tanker Brokers’ Panel (LTBP)". At first, they divided the groups as "General Purpose" for tankers under ; "Medium Range" for ships between 25,000 and and "Large Range" for the then-enormous ships that were larger than . The ships became larger during the 1970s, which prompted rescaling. The system was developed for tax reasons as the tax authorities wanted evidence that the internal billing records were correct. Before the New York Mercantile Exchange started trading crude oil futures in 1983, it was difficult to determine the exact price of oil, which could change with every contract.