The state of Minnesota may launch one of the largest natural gas safety initiatives in the country, following last month's house explosion in St. Paul.
State Fire Marshal Jerry Rosendahl said Wednesday night that his office may order sewer inspections across the state to look for mislaid gas lines.
Trista Meehan lost just about everything she owned on February 1, but she still considers herself lucky.
Her Highland Park home exploded, after a power drain auger hit a natural gas supply line that had accidently been run through an underground sewer pipe decades before.
"It was terrifying. I was in the house and all the sudden there was an extremely strong smell of gas and within seconds there was an explosion that shook the whole house," Meehan said. "Things went flying on the first floor. Multiple fires started immediately in my basement, and from what I understood, my whole house was engulfed in about five minutes."
The blast prompted an emergency inspection of dozens of nearby homes.
Xcel Energy operated the gas line linked to the blast. The company says it's now planning more than 50,000 additional inspections across Minnesota and North Dakota to look for similar problems.
"First phase of our project is the communities of St. Paul and South St. Paul," said Bill Kaphing, vice president of operations for Xcel Energy. He spoke Wednesday night at a neighborhood meeting about the problem in St. Paul.
"Simultaneously, we'll be doing what we call our targeted customers, schools, hospitals, nursing homes, that'll probably be about an additional 3,000 customers, across our service territory," he said.
The project could take more than two years, and use sewer crews from across the country. Still, even that may not be enough.
State Fire Marshal Jerry Rosendahl said Minnesota has more than 40 other gas distribution systems, and the Department of Public Safety may order all of them to check their systems for similar problems.
"I don't think we're going to be totally satisfied until we have a tremendous assurance that we have looked at everything that is out there that could possibly be a problem," Rosendahl said. "In combination with that, try to identify the program that we'll use to cover the rest of the state of Minnesota."
The cities of Cincinnati, Ohio and Lexington, Kentucky, recently launched similar programs. But Minnesota's would be the biggest and the first statewide re-examination of what is now considered a state-of-the-art method for laying gas pipe, wire and other underground utilities.
The technique is called horizontal directional drilling. It uses a hydraulic ram with a special steerable tip to tunnel under streets, yards and even rivers--instead of digging an open trench to lay wire and pipe.
The trouble is that the drills can bore unseen holes right through other underground utilities, like sewers. That can leave gas or electric lines vulnerable to damage from underground tools, such as sewer rooters.
Newer drills have special radio location devices to help avoid such collisions. But experts say some older tunneling projects were what were known as "point and pray" operations, with little or no regard for what might be in the way. Even new technology doesn't prevent accidents, such as the drill that hit a gas main and caused an Edina home explosion last month.
But there are still untold numbers of collisions hidden underground. Xcel officials say they've found more than 100 incidents where pipes have been found crossed in recent years. Four have led to gas leaks, and two to explosions, both in St. Paul.
The company did about 1,000 inspections following a blast seven years ago, and told state officials they thought they'd dealt with the problem.
But plumbers say they're still regularly stumbling on what are called cross-bores. Paul Gavic owns Benjamin Franklin plumbing in the Twin Cities. He offers drain services, including video inspection.
"We've seen a water line, an electrical line and a gas line in a West St. Paul sewer within the last year," Gavic said.
Gavic spoke after another meeting this week organized by the state's Office of Pipeline Safety. He's one of a growing number of experts who say sewer pipes -- particularly those between homes and streets -- should be checked every time there's been an underground drilling project nearby.
Trista Meehan agrees. She said the inspections planned by Xcel should be only a start, to avoid accidents like the underground drilling mistake that destroyed her home.
"I'm not sure that 50,000 is enough," Meehan said. "I think they may have to check every place they did install that."
Xcel officials say they hope to have plans in place by April 1, to prevent a repeat of the problem. They also hope to do most of the sewer inspections from the street, without having to enter homes.