Asphyxiant gas can smell the odorants, and assigning a different smell to each gas may be impractical. Another difficulty is that most odorants (e.g., the thiols) are chemically reactive. This is not a problem with natural gas intended to be burned as fuel, which is routinely odorized, but a major use of asphyxiants such as nitrogen, helium, argon and krypton is to protect reactive materials from the atmosphere. The dangers of excess concentrations of nontoxic gases has been recognized for centuries within the mining industry. The concept of black damp (or "stythe") reflects an understanding that certain gaseous mixtures could lead to
Oil and gas industry in the United Kingdom Oil and gas industry in the United Kingdom The oil and gas industry in the United Kingdom produced 1.42 million BOE per day in 2014, of which 59% was oil/liquids. In 2013 the UK consumed 1.508 million barrels per day (bpd) of oil and 2.735 trillion cubic feet (tcf) of gas, so is now an importer of hydrocarbons having been a significant exporter in the 1980s and 1990s. 98% of production comes from offshore fields and the services industry in Aberdeen has been a leader in developing technology for hydrocarbon extraction offshore. Historically most gas came from Morecambe Bay and