Category Archives: Utilities

A Kansas city must conduct tests to determine the corrosivity of the city’s water supply

McPherson’s Board of Public Utilities initiated plans to tackle the city water supply’s copper contamination, although the utility remains far from implementing any changes.

At its Monday meeting, board members were informed by BPU General Manager Tim Maier the utility received instruction from the state. Officials outlined what steps must be taken to lower copper levels in McPherson’s water supply and set a series of deadlines by which additional testing must be completed.

To work toward compliance with regulations set by the Environmental Protection Agency, BPU will take new samples from city households in an effort to determine which types of treatment will best rectify the problem. The utility is scheduled to have treatment recommendations prepared in the summer 2012.

BPU also must conduct tests to determine the corrosivity of the city’s water supply and prepare a plan to lower corrosion in water lines.

The corrosivity of water is not regulated by the EPA, though it contributes to the levels of restricted substances in the water supply. Most copper contamination, according to Maier, occurs in the copper pipes within households.

By lowering the corrosivity of the water, copper levels likely will  drop, as well.

In the city commission meeting conducted earlier on Monday, Maier said corrosion treatment recommendations are due in 2015.


PG&E replacing plastic pipes in Cupertino

A San Francisco  neighborhood is being made safer.

PG&E is replacing thousands of feet of dangerous plastic pipeline that carries natural gas. That kind of pipe has a history of failure and it did so recently in the very spot where PG&E is now changing it out.

PG&E crews began carving out sections of the street to gain access to the old plastic pipeline.

“The lines you see here along the road and outside the homes, those are the main lines and from the main line and from there branching out to the individual service lines that go directly to the meter,” PG&E spokesperson Brian Swanson said.

Twelve-thousand feet of pipeline will be replaced after a gas leak caused an explosion that rocked a Cupertino neighborhood on August 31.

The type of plastic used in Cupertino has failed in the past. The maker, had warned pipe made prior to 1973 can crack.

Assm. Jerry Hill, D-San Mateo, says there were other warnings.

“The National Transportation Safety Board in 1998 came out with a recommendation that the pipes should be checked, monitored and replaced; here again nobody did anything about it,” Hill said.

PG&&E claims it has.

Still, the utility company says replacing all plastic pre-1973 pipes was not priority until now.

PG&E will replace 1,200 miles of the plastic pipeline system wide, which will take at least four years.

Hill will now introduce legislation demanding that all safety recommendation made by the National Transportation Safety Board be adopted by all utility companies.


Corrosion – Fatal Impact on Concrete Wall Flaw

A deficiency in the concrete wall construction of the basin at the Gatlinburg Wastewater Treatment Plant led to the basin wall collapsing, killing two employees in April, a report from the state issued Thursday says.

“Walls were cast in a manner that produced a cold joint between the cast wall which fell” and three interior intersecting walls, according to the report from the Tennessee Occupational Safety and Health Administration (TOSHA).

TOSHA announced in early October that it found no safety violations at the plant, and this week released a five-page report that was the basis for that finding. When TOSHA announced in early October there were no safety violations, it didn’t give a probable cause of the basin wall collapse.

The new report does. What its inspectors call a “cold smooth joint” led to leakage of acidic waste across the joint, and “as a result, corroded the rebar splice couplers over a number of years.”

The couplers were not believed to have failed at one time, but gradually over the life of the basin, the report said.

When the findings of no safety violations were announced earlier this month, Veolia spokeswoman Karole Colangelo said, “Although the findings from TOSHA reinforce our emphasis on employee safety, it does not dismiss the fact that two Veolia Water employees perished in this tragic accident, and company employees continue to mourn their deaths.”

“It was assumed the two operators were making adjustments to the effluent flow inside the equalization basin,” the report says. While the men were working, the wall collapsed and fell on the building in which they were working.

The collapse sent about 850,000 gallons of untreated wastewater into the Little Pigeon River and forced the city to pump more untreated water into the river until it could come up with a temporary solution a few days later.

According to the workers’ last journal entry at 5:30 a.m. that day, the basin contained 1.3 million gallons of water and was 85 percent full. The water level was recorded at 25.5 feet. The report says interviews with operators and plant officials show the average water level was 4-8 feet.

The plant is owned by the city but managed by Veolia Water North America Operating Services LLC. Veolia officials told the state inspectors that both Crowder Construction Co., that built the plant and Flynt Engineering Co., that designed it are out of business. The basin was finished in 1996.

TOSHA learned that after the basin was finished in 1996 the north wall had cracks and a lateral displacement/bowing of the wall and walkway. Veolia told the state that buttresses were installed that “corrected” the problems with the wall and walkway.

TOSHA noted that the flow control building where the workers were is still not accessible, but the state says “we have no probable reason to think that access to this area would reveal any additional information that would result in citation being issued to Veolia.”

The report says the contractor used “splicing couplers” instead of dowels, as required in the original drawings, noting that while that was a “deviation” from the design, it was probably not the cause of the collapse. The report did say that “formation of a cold joint resulted in accelerated corrosion of the couplers.”

TOSHA reviewed the original design of the basin and found the design of walls “adequate.”


Waterville council considers $80 million natural gas line

Officials proposing to build an $80 million natural gas pipeline through central Maine got both support and questions at a City Council meeting earlier this week.

Mark Isaacson and Anthony Buxton, partners in Kennebec Valley Gas Co., are seeking a tax increment financing agreement with Waterville and 11 other communities on the proposed line, which would extend from Richmond to Madison and include 12 miles of line in the city.

Natural gas, they said, is less costly, cleaner and more efficient than oil.

City Manager Michael Roy said the city’s TIF Advisory Committee reviewed the project and voted to support it.

Councilor Karen Rancourt-Thomas, D-Ward 7, said she liked the idea that natural gas is less costly than oil and ultimately, would help companies maintain jobs.

“That’s what we have to look at in this situation,” she said.

Chris McMorrow, who owns rental properties, said heating buildings is costly and the introduction of natural gas would be welcome.

“So, I’m real excited as a landlord who buys a lot of energy,” he said.

But mayoral candidate Karen Heck cautioned councilors to seriously consider Isaacson and Buxton’s proposal, as well as a plan by Madison to build a pipeline.

She said she is concerned about where the gas comes from, how it is extracted and who extracts it.

Isaacson said a “host of companies” extract the gas and it is all mixed in the pipeline.

“We don’t have control over where the gas comes from,” he said.

Mayor Dana Sennett, who is running for re-election in November, said Wednesday that he thought the presentation Tuesday was informative.

“I think having a natural gas pipeline within the city’s limits and accessible to the city’s businesses and residential community is a long term asset as far as reducing energy costs,” he said.

Andrew Roy, who is running for mayor against Heck and Sennett, said he wants to learn more about the proposal before deciding if it is good for Waterville.

“There’s no way you can predict the price of it, 20 years down the road — 30 years down the road,” he said.

Madison is not asking communities along the pipeline route for tax breaks. Besides Waterville, Richmond, and Madison, they include Gardiner, Farmingdale, Hallowell, Augusta, Sidney, Oakland, Fairfield, Norridgewock and Skowhegan.

Isaacson said his company, which was formed last year, completed a preliminary design for the pipeline this year and received conditional certification in August from the Maine Public Utilities Commission, which allows the company to form as a public utility.

The company has completed a feasibility study but has not yet secured all funding needed for the project. Agreements with key users, identified as Huhtamaki, Sappi and Madison Paper Industries, are critical to the project.

The tax increment financing districts would require municipalities to give back a percentage of local property taxes to the developer to help finance the pipeline. TIF districts also act as a tax shelter for towns, so increased property values in the designated areas do not result in increased tax commitments.

Isaacson said the company hopes to get TIF agreements this year, secure financing in 2012 and build the pipeline in 2013.

Councilor John O’Donnell, D-Ward 5, asked what happens if the key users such as Madison Paper and Sappi do not come on board.

“Those commitments are essential for financing of the project,” Isaacson said.

O’Donnell asked what the advantages are over Madison’s plan.

Isaacson said Madison does not propose to provide residential or distribution service, at least in the beginning.

“I think their status as a public utility is unclear and their schedule is clearly behind ours,” he said.

Resident Scott McAdoo asked who would be responsible if a gas explosion occurred.

Buxton said gas pipelines are regulated by the local, state and federal government, and the standards are very rigorous.

“I would point out that we tend to hear about a natural gas accident when it happens, but it is extremely rare,” Buxton said.

He said Maine is about the only state in the nation without a natural gas infrastructure.

Council Chairman Charles Stubbert, D-Ward 1, said the city used to have a gas company and most people used gas. To his knowledge, there was never an explosion, he said.


US Senate approves pipeline safety bill

The Senate unanimously approved a pipeline safety bill that stemmed from a spate of incidents, including last year’s deadly explosion in San Bruno, California.

The measure had been held up by Sen. Rand Paul (R-Ky.), who lifted his hold after reaching agreement with Democrats to add a key recommendation from the National Transportation Safety Board.

Usually wary of regulatory oversight, Paul said he wanted to strengthen the legislation. His initial objection was that the bill was written before the NTSB completed its report on the San Bruno explosion, Paul said in a statement. “While I am in favor of as little regulation as necessary, if we are going to impose regulations, we should do it right,” he said.

But it does not include an NTSB recommendation to require automatic and remote-controlled shut-off valves on existing pipelines in heavily populated areas, a response to the nearly 95 minutes it took utility workers to manually shut off gas spewing from the San Bruno site. That requirement has faced industry opposition.

Gov. Jerry Brown recently signed state legislation to require automatic shut-off valves in vulnerable areas and ensure that gas companies pressure-test transmission lines in California.

“This is a huge step forward for the safety of pipelines and communities across the nation,” said Sen. Frank R. Lautenberg (D-N.J.), the measure’s chief sponsor. “This bill strengthens oversight and addresses long-standing safety issues that leave the public vulnerable to catastrophic pipeline accidents.”

The amended bill requires that older, untested pipes operating at high pressure — such as the one that exploded under San Bruno — be strength-tested to establish safe maximum operating pressures, Sen.Dianne Feinstein (D-Calif.) said after the vote.

“Simply put, Californians shouldn’t have to worry about streets exploding under their feet because of lax safety regulations,” Feinstein said in a statement.

A similar measure awaits action in the House.


PG&E to replace 1,200 miles of plastic gas pipe

Pacific Gas and Electric Co. will undertake a multiyear effort to remove more than 1,200 miles of plastic pipeline that has been linked to numerous failures nationwide, including two explosions in Northern California in the past six weeks.

The company’s decision to replace the pre-1973 pipe, marks a departure from a policy that PG&E had reaffirmed as recently as last week to assess its natural gas-distribution system before deciding which lines to replace.

The replacement project is likely to run into the millions of dollars, although PG&E would give no cost estimate. The company is likely to ask the California Public Utilities Commission to pass the cost along to customers.

The plastic pipe is used in distribution systems that deliver gas to homes. The manufacturer of the pipe warned customers nearly three decades ago that pipe made before 1973 was prone to cracking and sudden failure.

In 1998, the National Transportation Safety Board, noting instances in which this particular pipe and other plastic pipes had ruptured, urged pipeline companies to assess their lines and replace those with problems.

Two blasts
PG&E set aside $1.5 million in customers’ money starting in 2009 to assess its plastic pipelines’ reliability, but spent only a fraction of that and made little progress on the studies.

Then, on Aug. 31, one of these specific plastic pipelines in Cupertino that had sprung numerous leaks filled a condominium with gas, which ignited minutes after the owner had left. The building was destroyed. Less than a month later, another line installed in 1981 in Roseville (Placer County) exploded beneath a commercial intersection, touching off a seven-hour fire. No one was hurt.

PG&E said last Friday that it would start replacing pre-1973 plastic lines as soon as next year, after it presents a plan to state regulators. The company expects to take more than three years to complete the work.

First on the list
In the meantime, PG&E will replace 12,000 feet of line around the condominium complex in Cupertino and a 400-foot piece at the site of the Roseville fire. It will also replace distribution pipe at a mobile home park in St. Helena where a leak was discovered last year, PG&E spokesman David Eisenhauer said.

The company said it plans to digitize 15,000 maps of the plastic pipeline systems and create a database to track leaks. PG&E will also replace some of the 6,676 miles of newer lines based on how often they leak.

Eisenhauer said the effort is in the planning stages and carries unknown costs and time frames.

“This is something we have been looking at,” he said. “Part of the plan is determining where in our system there is a higher leak rate, and then prioritizing it.”

Assemblyman Jerry Hill, D-San Mateo, has announced plans for legislation to require state regulators to act on National Transportation Safety Board recommendations, which could lead to an order for PG&E to remove its troubled plastic pipe.

‘Great news’
“I think it’s great news – it’s certainly an indication of good will in the future,” Hill said. “But we still need the legislation, to make sure safety recommendations are followed.”

Richard Kuprewicz, a pipeline consultant who advises the advocacy group The Utility Reform Network as well as the federal government on safety issues, said PG&E may be able to replace some of its lines without digging up the old pipe.

In some cases, new plastic pipe can be inserted in old lines, and in others PG&E can create a new distribution network around the old one, Kuprewicz said.

“It’s a fairly easy process,” he said, “but the devil’s in the details” – specifically, finding out which lines need to be replaced first.

“It’s very important that it be matched with a well-thought-out leak survey process,” Kuprewicz said.


Manhattan Residents expressed fears for proposed 30-inch high pressure Natural Gas Pipeline

West Side residents expressed their fears at a Tuesday Community Board 2 forum about a proposed 30-inch, high-pressure, natural gas pipeline crossing the Hudson River from New Jersey to Gansevoort St.

The Spectra Energy pipeline between Linden, N.J., and the West Village has the support of the Bloomberg administration, which has mandated that thousands of residential furnaces using high-polluting No. 4 and No. 6 heating oil be converted in the next few years to relatively clean-burning natural gas.

Jason Mansfield, chairperson of the C.B. 2 Environmental, Public Health and Safety Committee, said the forum was intended to help draft the board’s response to the FERC review before the Oct. 31 deadline for public comment.

The federal agency is holding a meeting in Greenwich Village at P.S. 41, W. 11th St. at Sixth Ave., at 7 p.m. Thurs., Oct. 20, to take public testimony.

“This is an important meeting since your comments will be entered into the record and FERC can hear from you firsthand,” Mansfield said at opening of the Tuesday forum. The Oct. 4 pipeline forum was the committee’s third in two years.

Later this week the public will be able to file comments on the project directly with FERC online through the C.B. 2 Web site at

Representatives of Spectra Energy, Con Edison and the city Department of Environmental Protection spoke at length about the need for the pipeline and the safety measures to be employed in its construction and operation.

But opponents insisted they were not convinced that a new natural gas source was really needed, much less a large, high-pressure line with potential safety risks.

Regarding safety, one member of the audience demanded, “How can we trust you?” citing the Sept. 9, 2010, explosion and fire from Pacific Gas & Electric’s natural gas line that destroyed 53 homes, damaged 120 other buildings and killed one person in San Bruno, California, near San Francisco.

Spectra said the proposed pipeline would have specially made and inspected high-strength flexible pipe with coating inside and out, buried 3 feet or more with special fill. In operation, technicians monitoring operations via robotics could remotely shut down the line.

But C.B. 2 members noted that the board last year suggested that automatic shutoff valves might be more reliable than remote control shutoff. However, Spectra representatives at the Tuesday forum said technology for remote shutoff was better than automatic shutoff technology.

“A lightning strike could trigger an automatic shutoff,” said Ed Gonzales, Spectra project manager.

The Spectra pipeline under review would cross the southwest corner of Gansevoort Peninsula, cross the West Side Highway at Gansevoort St. and terminate on the west side of the proposed Whitney Museum property.

Con Edison would build its own high-pressure, 30-inch, natural gas line from the Gansevoort terminus of the Spectra pipeline along 10th Ave. for 1,500 feet to a Con Edison connection at 15th St. at 10th Ave.

But the Con Edison connector line is not part of the FERC environmental review. Cheryl Payne, the engineer in charge of Con Edison’s gas transmission, said the connector line has not been designed yet. But she said the materials and construction method would conform to the same high standards of the Spectra pipeline.

The Con Edison connector line would also use a remote shutoff system. Like the Spectra representative, Payne said an automatic shutoff system could be triggered by an event like lightning and needlessly leave large areas of the city without service.

C.B. 2’s Mansfield said later that the environmental review of the Spectra project should include Con Edison’s connector line.

“I don’t think they really made the case that the pipeline is needed,” he added. “It just wasn’t justified in view of its potential for catastrophic damage.”

Many of the project’s opponents at the Tuesday meeting had in mind the impending rules on natural gas production by high-volume hydrofracture drilling in New York State’s Southern Tier.

Spectra representatives said the company’s business was only natural gas transportation, not production. Indeed, the draft environmental impact statement indicates that the pipeline would be able to bring natural gas from the Marcellus Shale regions of southern New York and northern Pennsylvania into the Manhattan.

Catherine Skopic, an environmental advocate, told the Oct. 4 forum that it was time for investment and exploration of renewable resources like solar voltaic cells and wind energy instead off fossil fuel.

Opponents were also skeptical about the common assumption that natural gas is the cleanest of fossil fuels, if the environmental damage of hydrofracture drilling is included in the assumption.

Speaking to the fear of terrorism, Frank Eady, a former member of Community Board 4, raised the specter of Stuxnet, a computer program that he said was used to sabotage and set back Iran’s nuclear weapons program.

“That program is out there,” he warned.

Spectra representatives acknowledged that they didn’t know about Stuxnet, but Gonzales said the company monitored potential cyberspace danger.

Mav Moorhead, a Lower Manhattan resident angrily demanded, “Who will be accountable when the neighborhood blows up?” she said, adding, “We don’t have a hospital,” referring to the closing of St. Vincent’s.


NJ Reservoir Drainage May Affect Local Drinking Water

Officials say water may look, smell differently, but is still safe to drink while the Cedar Grove Reservoir is drained.

While the Cedar Grove Reservoir is drained, workers will go in and repair corrosion damage, inspect its conduits and fix leakage.

The process of draining the reservoir, which is located along Ridge Road, is expected to take three to four months. During that time, water customers in towns supplied by the reservoir may notice some discoloration or changes to the taste of the water, but officials say the water is safe to drink.

The City of Newark owns the reservoir and the city’s Department of Water and Sewer Utilities for the City of Newark along with Mayor Cory A. Booker, explained that the discoloration occurs when valves are opened and closed during the drainage process. The Great Notch reservoir, owned by the Passaic Valley Water Commission and located in Woodland Park, will supply additional water to customers, so there is no interruption in the supply or quality of water while the repair work is being done.

“We are working to upgrade and modernize our water system and to provide residents with the highest quality water supply in the nation,” said Booker. “This repair work will require us to drain and inspect the Cedar Grove Reservoir, which may cause temporary discoloration or a change in the water’s taste. But the water provided will be safe to use.”

City officials say there is a leak in the outlet tunnel and corrosion damage to the 60-inch water main. The main also needs a new valve.

The reservoir provides water for Newark, Belleville, Bloomfield, and some areas of East Orange. Every decade or so, the reservoir is drained and cleaned of debris. Its pipes are inspected, and then it is re-filled. The project is expected to finish on April 30 of next year, according to Township Manager Thomas Tucci, who said the project will not create any issues to residents.

The city has not drained the reservoir since 1990 to perform repairs. Water samples are taken daily from the reservoir and tested to make sure the water quality complies with safe water drinking standards. Discoloration does not make the water unsafe, officials say, but could cause discoloration while washing clothes.

“There may be some slight color changes during the switchover,” said Andrew Pappachen, Director of Operations for the Newark Watershed Conservation and Development Corp. “However, we will ensure the potability by maintaining sufficient chlorine residual in the water. We will be monitoring the water quality more often.”


Lawsuit leaves large gas storage fields in Kansas unregulated

Bill Knox knows to respect natural gas. He’s a former oil- and gas-field worker who helped lay the foundations for a mammoth underground gas storage operation three miles from his home; he lost a friend in a gas explosion in Texas; and he well remembers 10 years ago when gas escaped from underground storage and blew up in Hutchinson, 40 miles northeast of Cunningham, killing an elderly couple.

Knox says it’s unsettling to know that because of a federal court decision last year, neither the state nor federal governments are inspecting the gas field near his home, or others holding thousands of times the amount of gas that caused havoc in Hutchinson.

“Any time you’ve got gas going, you need to have it inspected every now and then,” Knox said. “If we get a leak and it’s not detected or the pipe gets weak and nobody ever inspects it, we could have an explosion like Hutchinson.”

Since the federal district court in Topeka struck down Kansas gas-safety laws last year, 11 underground storage sites with a capacity of more than 270 billion cubic feet of gas have gone uninspected for 18 months, according to state officials.

The state can’t inspect them.

The federal government has chosen not to.

As a result, thousands of Kansans live on and around uninspected gas-storage fields that dwarf the system that caused the Hutchinson disaster.

The gas company that sued Kansas says it’s not a concern, that internal inspections and policies are enough to ensure public safety.

“We’re committed to the safe, reliable and efficient operation of our pipeline systems, related infrastructure, and storage facilities in Kansas and in all areas where we operate,” said a statement from Richard Wheatley of the Colorado Interstate Gas Co.

Earlier this year, members of the state House and Senate voted unanimously to ask the federal government to restore the state’s authority to regulate interstate gas storage.

Two joint resolutions got snagged in Statehouse scheduling, so the House sent its own unanimous resolution to Washington.

So far, it seems to have been ignored.

“I guess when we have the next field blow up, maybe the feds will figure out they did it wrong,” said Rep. Carl Holmes, R-Liberal, chairman of the House Energy and Utilities Committee and vice chairman of a special committee that studied underground storage safety last year.

“Everything was going fine, we had some of the toughest rules in the nation until the feds came in and intervened,” Holmes said.

Both Holmes and Senate Energy Committee chairman Pat Apple, R-Louisburg, said they expect to revive the joint resolutions when the Legislature returns to session in January.

When gas escapes

Kansas is Exhibit A for what can happen when gas escapes from an underground storage facility.

In January 2001, gas leaked from an underground salt cavern at Yaggy and flowed seven miles underground to Hutchinson, where it popped up through abandoned brine wells and exploded.

The first explosion destroyed about half a block of downtown businesses and shattered glass for blocks around, but no one was killed.

A day later, gas found another path to the surface and exploded in a mobile home park in east Hutchinson, killing an elderly couple.

It took more than a month for flares to burn off the estimated 143 million cubic feet of gas that escaped from storage.

The downtown businesses were never rebuilt, the mobile home park was closed and the Yaggy field was shut down, although it owners are still slowly drawing down the gas under the supervision of the Kansas Department of Health and Environment.

Following the accident, the Legislature voted to have two state agencies split responsibility for regulating underground storage of hazardous gases and liquids.

KDHE would regulate man-made underground salt caverns like Yaggy, the only salt storage in the state currently holding natural gas.

The Kansas Corporation Commission (KCC) would regulate “porosity” fields, where high-pressure gas is pumped into depleted oil fields, gas fields and reservoirs and held until it is piped out to customers.

Following last year’s court order, the KCC continues to regulate storage fields that do business only within the state.

But according to federal records, those eight fields hold only 12 billion cubic feet of gas, a fraction of the 272 billion cubic feet of capacity in the interstate storage fields the state is no longer allowed to regulate.

“We need to ensure that these (interstate) facilities are operated in a safe manner,” said KCC spokesman Jesse Borjon. “They should be regulated to the same standard as the intrastate facilities currently regulated by the KCC.”

Federal response

Officials of the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Division, the federal agency responsible for interstate gas transport safety, declined to comment.

A spokeswoman for the agency requested written questions, which went unanswered.

But department records show that DOT considered and rejected federal standards for underground storage after a devastating propane explosion killed two people in Brenham, Texas in 1992 — nine years before Hutchinson’s disaster.
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Search for gas leaks in Seattle cut short before blast

Puget Sound Energy says electrical arcing caused by a fallen tree created holes in natural-gas pipes, leading to an explosion at a North Seattle house.

After a rare electrical problem blew four holes in natural-gas pipes in Seattle’s Pinehurst neighborhood on Sunday, Puget Sound Energy says, the agency went house to house in the neighborhood to check for more leaks. Its workers stopped at nightfall, without finding more.

It wasn’t until the next day, after a huge explosion and house fire, that PSE did a much larger “leak survey” across a 5-square-mile area, working into the night. Crews found four more leaks, but say at least three are unrelated.

With customers and Seattle residents rattled Tuesday, PSE defended its initial search. Sunday’s testing area — which stopped just blocks short of the explosion site — focused on areas with similar pipe, said Martha Monfried, PSE’s communications director.

She said it would not have been safe to continue the leak survey into the night. “You can’t do residential survey work in the dark, for both worker safety and for the comfort level of homeowners,” she said.

But Mark McDonald, a natural-gas expert who speaks about catastrophic leaks, said PSE should have gone farther.

“I would go at least 10 blocks in every direction to make sure we got all the leaks,” said McDonald, president of the New England Gas Association, an umbrella group of unionized utility workers. “Night, storm, whatever, you go farther than you need to be safe. It obviously was a mistake.”

Storm blamed for “arcing”

The source of the leaks, according to the utility, originated during a windstorm Sunday.

At about 11:30 a.m., a tree came in contact with one of the three overhead electrical distribution lines on Northeast 127th Street between 12th Avenue Northeast and 10th Avenue Northeast, said Seattle City Light spokesman Scott Thomsen. The incident tripped the breakers and the circuit quickly shut off.

“Our equipment’s role is to ground out that short, and the system operated the way it’s designed to operate,” said Thomsen.

According to PSE, the electrical current, conducted through the tree, energized a wrapped steel natural-gas pipe, causing a problem known as “arcing.” The current blew a series of BB- or finger-sized holes in the pipe, according to the utility.

On Tuesday, PSE said the supply pipe and gas meter found at the blast site showed a hole just inches outside the Ingham home, at 12312 Fifth Ave. N.E., about seven blocks from where the power tripped Sunday.

The natural-gas service line to their home was pressurized at 45 pounds per square inch, according to PSE. It won’t be clear until an investigation is completed how the gas got into the home, but experts theorized that the gas could have leaked in through a foundation.

Seattle Fire Department spokesman Kyle Moore confirmed that investigators determined there was an accumulation of gas inside the house. But it wasn’t clear if the buildup was from the leak outside the house or from a second leak that might have occurred inside, he said.

Two engineers from the state Utilities and Transportation Commission (UTC) are investigating Monday’s fire and explosion, as well as PSE’s response to Sunday’s gas leaks.

Dave Lykken, pipeline safety director for the commission, said the neighborhood’s natural-gas pipes are probably 1960s-vintage — with some new plastic pipe — and are considered safe.

UTC requires utilities to routinely check natural-gas pipelines for corrosion. PSE said it conducts neighborhood leak surveys every three years; it last checked the Pinehurst area in November 2008, said Andy Wappler, a PSE spokesman.

In the more exhaustive survey ordered after the explosion, PSE found four new leaks, but said at least three were unrelated and characterized them as small enough that they would be treated as scheduled — rather than emergency — repairs in a different situation. The other leak remains under investigation.

A third survey began Tuesday, and a fourth is planned.