Many North American homes sit peacefully above a cat鈥檚 cradle of pipelines and wires, culverts and cables. Long buried. Long forgotten. Forgotten, that is until a backhoe hooks a sewer pipe or a plumber pierces a gas line and then the unthinkable happens: a spark; a fire; an explosion -- and that peaceful neighbourhood is consumed in a catastrophe of flame and smoke and death. Three years ago, Trista Meehan was lucky to escape just such a home explosion with her life.
It all began when Trista noticed a problem in her basement. She had recently bought her 鈥渄ream home鈥� in a quiet neighbourhood of St. Paul, Minnesota but after moving in noticed that her sewer had backed-up. Trista, never one to shy away from a dirty job, rented a plumber鈥檚 snake and rolled up her sleeves. For hours she twisted and turned, pushed and pulled but no matter how hard Trista tried she simply could not clear the blockage.
The next step? She called a professional plumber who brought in a power-driven snake with a razor-sharp cutting bit. The problem however was that the blockage was not a normal accumulation of household debris. Rather, Trista鈥檚 sewer pipe had been a natural gas line running through it and when the plumber鈥檚 snake sliced through the fragile PVC of the gas pipe, a flash fire and then an explosion ensued. The plumber was badly burned and Trista barely escaped with her life. Her home and all her belongings were lost.
鈥淚t felt like the house had been bombed鈥�, she recalled, in an interview with W5鈥檚 Tom Kennedy. 鈥�(The plumber)鈥ame running up the stairs telling me to get out! Everything was on fire. It was an inferno.鈥�
Trista鈥檚 near-deadly problem was that the gas line had been inadvertently installed through her existing sewer line. Industry professionals, such as Professor Mark Knight at the University of Waterloo, call this situation a cross-bore. Knight has been studying cross-bores for years and notes that with the advent of 鈥渢renchless technology鈥� and the rapid growth of utility and telecommunications below-the-ground installations 鈥� 鈥榦ut of sight, out of mind鈥� is a dangerous assumption for home owners to make.
No one knows how many cross bores exist in Canada and the USA. But an American estimate suggests that in older neighborhoods where consumers have recently converted to gas, there could be as many as two cross bores per kilometer. Canada鈥檚 gas companies encourage Canadians to always 鈥淐all Before You Clear.鈥� If your sewer is blocked, call the gas company before sending a snake down.
But the problem is one of both casual engineering and careless human behaviour. Messages often don鈥檛 register with people unless they are accompanied by tragedy. So far, Canadians appear to have been lucky.
