10 August 2004 Sask. Residents Go Home After Train Derailment Estevan - More than 150 people were heading back to their homes and businesses Tuesday after being evacuated because of a derailment involving train cars carrying hazardous chemicals.   The six Canadian Pacific Railway cars went off the tracks at a crossing in downtown Estevan Sunday. Five contained anhydrous ammonia - used in fertilizers and household detergents.   "We are at the stage now with the clean-up of the anhydrous ammonia that we can start letting people back to their homes and businesses," said CP spokesman Ed Greenberg. "We have asked the city to lift the evacuation order."   The ammonia was contained within the tankers that had toppled onto their sides.   In low concentrations, the release of the chemical into the atmosphere can cause irritation to the eyes. High concentrations can burn skin and cause respiratory problems.   An estimated 150 to 200 people were removed from their homes, including residents of a nearby seniors' facility. No one was injured.   The city found lodgings for some people while others opted to stay with family and friends.   The cause of the derailment was still unknown. A full investigation will be conducted once the initial cleanup is finished.   Some Estevan residents are questioning the safety of allowing dangerous goods to be transported through the community on a regular daily basis.   A major CPR derailment in 2002 involving anhydrous ammonia killed a 38-year-old man and injured many more in Minot, N.D.