LAC-MEGANTIC, Que. - Some residents of Lac-Megantic heard discouraging news on the one month anniversary of the fiery train derailment.

People who remain evacuated from their homes were told at a meeting on Tuesday that they won‘t be able to return to their dwellings for at least a year.

Ministry of the Environment officials said significant decontamination work is still required in the epicentre of the disaster once known as the "red zone."

They said if the soil is too contaminated, some residents may never be able to return to their homes.

Earlier Tuesday, police transferred control of the hardest hit area to the city, which has hired a security company to keep watch on the devastated downtown zone.

A train hauling crude oil derailed and exploded in Lac-Megantic on July 6, destroying much of the downtown core and killing at least 47 people.

Both the Quebec provincial police and the Transportation Safety Board of Canada continue to investigate the disaster.

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  • Firefighters continue to water smoldering rubble Sunday, July 7, 2013 in Lac Megantic, Quebec. A runaway train derailed Saturday igniting tanker cars carrying crude oil.

  • The downtown core lays in ruins as firefighters continue to water smoldering rubble Sunday, July 7, 2013 in Lac Megantic, Quebec. A runaway train derailed Saturday igniting tanker cars carrying crude oil.

  • The remains of tanker cars lie burnt out in the downtown core Sunday, July 7, 2013, in Lac Megantic, Quebec. A runaway train derailed Saturday igniting tanker cars carrying crude oil and devastated the town.

  • The downtown core lays in ruins as firefighters continue to water smoldering rubble Sunday, July 7, 2013 in Lac Megantic, Quebec. A runaway train derailed Saturday igniting tanker cars carrying crude oil.

  • The downtown core lays in ruins as firefighters continue to water smoldering rubble Sunday, July 7, 2013, in Lac Megantic, Quebec. A runaway train derailed Saturday igniting tanker cars carrying crude oil.

  • The downtown core lays in ruins as fire fighters continue to water smouldering rubble Sunday, July 7, 2013 in Lac Megantic, Quebec after a train derailed ignited tanker cars carrying crude oil.

  • The downtown core lays in ruins as firefighters continue to water smoldering rubble Sunday, July 7, 2013, in Lac Megantic, Quebec. A runaway train derailed Saturday igniting tanker cars carrying crude oil.()

  • The downtown core lays in ruins as firefighters continue to water smoldering rubble Sunday, July 7, 2013 in Lac Megantic, Quebec. A runaway train derailed Saturday igniting tanker cars carrying crude oil.

  • The downtown core lays in ruins as fire fighters continue to water smoldering rubble Sunday, July 7, 2013 in Lac Megantic, Quebec after a train derailed ignited tanker cars carrying crude oil.

  • Burnt out oil tank cars and the destroyed downtown core lays in ruins as firefighters continue to water smouldering rubble Sunday, July 7, 2013, in Lac Megantic, Quebec.

  • The downtown core lays in ruins as firefighters continue to water smoldering rubble Sunday, July 7, 2013, in Lac Megantic, Quebec, after a train derailed ignited tanker cars carrying crude oil. The runaway train derailed, causing explosions and fires that destroyed the downtown district.

  • The downtown core lays in ruins as firefighters continue to water smoldering rubble Sunday, July 7, 2013, in Lac Megantic, Quebec, after a train derailed ignited tanker cars carrying crude oil.

  • Burnt out oil tank cars and the destroyed downtown core lays in ruins as firefighters continue to water smouldering rubble Sunday, July 7, 2013, in Lac Megantic, Quebec. A runaway train derailed igniting tanker cars carrying crude oil on Saturday.

  • An aerial view of a fire in the town of Lac-Megantic is seen from a Sûreté du Québec helicopter Saturday, July 6, 2014 following a train derailment the sparked several explosions in Lac Megantic, Quebec.

  • Smoke rises from railway cars that were carrying crude oil after derailing in downtown Lac Megantic, Quebec, Canada, Saturday, July 6, 2013.

  • Smoke rises from railway cars that were carrying crude oil after derailing in downtown Lac Megantic, Quebec, Canada, Saturday, July 6, 2013.

  • Smoke rises from railway cars that were carrying crude oil after derailing in downtown Lac Megantic, Quebec, Canada, Saturday, July 6, 2013.

  • Smoke rises from railway cars that were carrying crude oil after derailing in downtown Lac Megantic, Quebec, Canada, Saturday, July 6, 2013.

  • Smoke rises from railway cars that were carrying crude oil after derailing in downtown Lac Megantic, Que., Saturday, July 6, 2013.

  • Smoke rises from railway cars that were carrying crude oil after derailing in downtown Lac Megantic, Quebec, Canada, Saturday, July 6, 2013.

  • This aerial photo shows a fire in the town of Lac-Megantic as seen from a Sûreté du Québec helicopter Saturday, July 6, 2013 following a train derailment that sparked several explosions in Lac Megantic, Quebec.

  • MORE LAC MEGANTIC PHOTOS

  • A levelled building is seen in the foreground the day after a train derailed causing explosions of railway cars carrying crude oil Sunday, July 7, 2013 in Lac Megantic, Que.

  • Canadian Prime Minister Harper, right, surveys the scene Sunday, July 7, 2013 in Lac Megantic, Quebec, as firefighters continue to spray derailed tanker cars. A runaway train derailed Saturday causing explosions of railway cars carrying crude oil and destroyed part of the downtown area of Lac Megantic.

  • Prime Minister Harper, centre, talks with firefighters Sunday, July 7, 2013 in Lac Megantic, Quebec. A runaway train derailed Saturday exploding tanker cars carrying crude oil and destroying part of the downtown area of Lac Megantic.

  • Prime Minister Stepen Harperwaves to people as he visits the site Sunday, July 7, 2013 in Lac Megantic, Quebec, where a runaway train derailed Saturday. Tanker cars carrying oil exploded after the derailment and destroyed the business district in Lac Megantic.

  • Firefighters keep watering railway cars the day after a train derailed causing explosions of railway cars carrying crude oil Sunday, July 7, 2013 in Lac Megantic, Que.

  • The downtown of Lac Megantic, Que. is seen Sunday, July 7, 2013, the day after a train derailed causing explosions of railway cars carrying crude oil.

  • Burnt buildings are seen following a train derailment causing explosions of railway cars carrying crude oil Sunday, July 7, 2013 in Lac Megantic, Que.

  • Workers inspect a railway car that was part of a convoy of railway cars carrying crude oil that derailed Saturday causing explosions Sunday, July 7, 2013 in Lac Megantic, Que.

  • Workers inspect a railway car that was part of a convoy of railway cars carrying crude oil that derailed Saturday causing explosions Sunday, July 7, 2013 in Lac Megantic, Que.

  • A fire keeps burns after railway cars that were carrying crude oil derailed in downtown Lac Megantic, Quebec, Saturday, July 6, 2013.

  • Firefighters douse a blaze after a freight train loaded with oil derailed in Lac Megantic in Canada's Quebec province on June 6, 2013, sparking explosions that engulfed about 30 buildings in fire. At least one person has been killed.

  • Smoke rises in the background as Quebec Premier Pauline Marois speaks to reporters after a freight train loaded with oil derailed in Lac Megantic in Canada's Quebec province on June 6, 2013, sparking explosions that engulfed about 30 buildings in fire. At least one person has been killed.

  • Residents watch rising smoke after a freight train loaded with oil derailed in Lac Megantic in Canada's Quebec province on June 6, 2013, sparking explosions that engulfed about 30 buildings in fire. At least one person has been killed.