Texas Low Emission Diesel standards (TxLED) are rules regulating the quality of diesel fuels, intended to reduce pollutants (especially NOx). Since Oct. 31, 2005, diesel fuel to be consumed by mobile sources in the 110 affected counties in Eastern Texas must meet these requirements:
Alternatively, diesel fuel that complies with the specifications of a California Air Resources Board (CARB) certified alternative diesel formulation that was approved by CARB before January 18, 2005 may be used, as can fuel approved by the Texas Commission on Environmental Quality (TCEQ) that is proven to have emissions equivalent to or less than TxLED compliant fuel.