Synthetic fuel the fuel, and the fuel is less dense than conventional jet fuel allowing aircraft to fly further on the same load of fuel. The "cleanness" of these FT synthetic fuels is further demonstrated by the fact that they are sufficiently non-toxic and environmentally benign as to be considered biodegradable. This owes primarily to the near-absence of sulfur and extremely low level of aromatics present in the fuel. One concern commonly raised about the development of synthetic fuels plants is sustainability. Fundamentally, transitioning from oil to coal or natural gas for transportation fuels production is a transition from one inherently depletable
Fuel dyes of the same red dyes, in fivefold concentration, for tax-exempt diesel fuels such as heating oil; their argument for the higher dye content is to allow detection even when diluted with "legal" fuel. Detection of red-dyed fuel in the fuel system of an on-road vehicle will incur substantial penalties. Organised crime gangs may "launder" low-price dyed fuel, removing the dye and selling it illegally to unsuspecting motorists at the higher price of undyed fuel. Paramilitary groups connected to political unrest in Northern Ireland have established laundering plants on both sides of the Irish border. In 2004, Northern Irish police discovered