Fuel oil and related equipment which were often designed for lighter fuels. For comparison, BS 2869 Class G heavy fuel oil behaves in similar fashion, requiring storage at , pumping at around and finalising for burning at around . Most of the facilities which historically burned No. 6 or other residual oils were industrial plants and similar facilities constructed in the early or mid 20th century, or which had switched from coal to oil fuel during the same time period. In either case, residual oil was seen as a good prospect because it was cheap and readily available. Most of these facilities
Ethanol fuel by country label blends containing fuel ethanol on the dispenser. Due to ethanol's greater stability under pressure it is used by Shell in their 100 octane fuel. Similarly IFS add 10% ethanol to their 91 octane fuel, label it premium fuel and sell it more cheaply than regular unleaded. This is converse to the general practice of adding ethanol to a lesser quality fuel to bring its octane rating up to 91. Some concern was raised over the use of ethanol blend fuels in petrol vehicles in 2003, yet manufacturers widely claimed that their vehicles were engined for such fuels. Since then