Canada is developing regulations to control air pollutant emissions under the Railway Safety Act. The proposed regulations would be aligned with those of the U.S., and would apply to federal railway companies operating in Canada. The Government of Canada has a Memorandum of Understanding with the Rail Association of Canada to align with U.S. EPA Tier 4 standards for locomotive emissions. There is also a 15 ppm limit for sulphur in diesel fuel produced or imported for use in locomotives under the Sulphur in Diesel Fuel Regulations.