According to The Columbus Dispatch on August 29th:

Columbia Gas faces a possible $400,000 fine for a gas explosion that destroyed an Upper Arlington house and made eight other homes uninhabitable.

But there’s another party that “contributed” to the blast earlier this year, according to the Public Utilities Commission of Ohio, and it involves a card in the Columbus Division of Water files.

The “tap card,” dated 1990, identified a buried abandoned gas line as an active waterline at Hidefumi and Mariko Ishida’s home, 3418 Sunningdale Way.

A Columbus water employee, thinking he was closing a waterline to the house, actually opened the old gas line. That led to the explosion on March 21, the PUCO report says.

How the card ended up in the file, and whether it contributed to the error, was unclear, PUCO spokesman Matt Schilling said.

“That’s kind of the big mystery,” Schilling said. The file also contained a 1960 tap card correctly identifying the location of the waterline going into the house.

Water Division spokeswoman Laura Young Mohr said the division is still reviewing the PUCO report and had no comment on Friday.

The staff report, released on Friday afternoon, recommends the $400,000 fine for Columbia Gas. It also says that the utility needs to “proactively identify inaccurate curb box locations” in its pipeline system. The report notes that the PUCO does not have jurisdiction over the water division.

PUCO commissioners will decide whether to fine Columbia Gas and by how much, Schilling said. They have no deadline.

The staff report concluded that Columbia Gas had failed to properly disconnect the old gas line and fill the box with concrete. Columbia spokesman Dave Rau said the company found no documents that it had been notified to disconnect the line.

The staff report listed the series of events leading up to the explosion:

• On March 13, a Columbus water employee who was turning water off at the Ishidas’ home for repairs found two in-ground boxes, each with a lid marked “water.” He broke the lid to access the one in the driveway apron (actually the abandoned gas line) and replaced it with a black lid labeled “water.” He turned the water off at a separate curb box and painted that lid blue to designate it as the working water valve.

• The day before the explosion, on March 20, another water-department worker arrived to turn off the water because the Ishidas were leaving on an extended vacation to Japan. He opened the box in the driveway apron (the abandoned gas line) and dug through gravel to turn the valve, then noticed the blue-painted curb box. He turned off the water at the curb box.

He thought he had turned off the driveway valve, but hadn’t. He checked the gas meter and saw the needles weren’t moving, but he didn’t know that was because the old line wasn’t running through the meter. Natural gas began seeping through the uncapped end of the old pipe at the home’s foundation.

• The next day, on March 21, a mail carrier smelled natural gas as he passed the Ishida home. He told a neighbor, who called Columbia Gas. About 20 minutes later, a Columbia Gas worker arrived. He turned off the gas but continued to find high concentrations near the foundation, not knowing about the abandoned gas line that was leaking.

He called the utility about 1 p.m. to report a gas leak and was waiting for a special “purge” crew to arrive when the house exploded about 2:40 p.m.

The Ishidas were not at home and no one was injured in the explosion and fire. Their home was destroyed and 28 other homes were damaged. Eight of those are uninhabitable.

A Columbia Gas crew sifting through debris to stop the leak finally discovered the abandoned gas valve under the box labeled “water.”