Non-road (e.g. agriculture and construction equipment) diesel must contain a red dye to identify spills and leaks. Beginning June 1, 2006, non-road diesel is not required to contain red dye when it leaves the refinery gate and may be dyed at the distribution terminal. On-road diesel fuel must not contain this red dye.
Home Heating Oil must contain the marker Solvent Yellow 124. Because the marker is not visible, any marked heating oil must also contain a visible trace of red dye. All on-road and non-road diesel must be marker free.