Investigators said Tuesday a lack of safety equipment may have been a factor in the train derailment and explosion that killed at least 13 people in Quebec. The death toll is expected to rise, as police said dozens of people were still missing and more than 30 buildings in Lac-Megantic were destroyed when a Montreal, Maine & Atlantic Railway runaway train crashed about 155 miles east of Montreal. Environment Quebec was looking into the possibility hundreds of thousands of gallons of oil got into soil and the Chaudiere River. Transportation Safety Board of Canada lead investigator Don Ross told a news conference the area around Lac-Megantic \"is not equipped with the type of signal systems that would even show to a rail traffic controller that something was moving on the territory that they hadn\'t authorized.\" TSB investigator Ed Balkaloul said the routine use of tanker cars like those involved in the crash to carry flammable materials has been a matter of concern for safety officials since 1995, when a derailment in Gouin, Quebec, resulted in a sulphuric acid leak into the Tawachiche River and a lake, the Canadian Broadcasting Corp. reported. \"We\'ve had a long record of advocating to further improvements to many of these ... because they\'re a very common type of tank car and take a lot of very large volumes of petroleum products, like in this case, and you can see the damage that was caused here,\" Ross said. An estimated 1,200 residents of Lac-Megantic were permitted to return to their homes Tuesday, The (Montreal) Gazette said.