The Russian Roulette of leaky gas pipes

Some Baltimoreans had just comforted themselves that a massive explosion like the one in Beirut would not happen in here, no matter how many complaints there are about the competence of local government. Nobody would put thousands of tons of Ammonium Nitrate into a warehouse and then throw away the keys. But then three Baltimore rowhouses blew away on a bright and sunny summer morning, just like that. The destruction happened on a much smaller scale than in Beirut, but what neighbors stared at in the 4200 block of Labyrinth Road in Baltimore's Milbrook neighborhood looked quite similar to what happened in Lebanon.

What's left of three rowhouses in Park Heights

Three houses were entirely flattened, people were trapped in the rubble and neighbors could feel the blast wave blocks away where it blew windows and doors out of their frames and knocked people and items over in the process. On a hot and humid Monday morning, the only plausible explanation for the blast is natural gas. The cause, however is officially unknown as of this writing. Gas is carried through lines which crisscross the city almost under every street, providing a fairly clean and efficient source of heat for furnaces, hot water heaters, dryers and stoves in tens of thousands of homes for a total of over 600,000 customers in City and County. Each of these appliances can be faulty and cause a leak.

The homes on Labyrinth Road were not some abandoned vacant structures with squatters in them, but neat home-owner or renter-occupied  houses with front and back yards in a block with one gap. The gap was adjacent to the three destroyed homes, which is why some initial reports spoke of four destroyed homes.

The three houses from the left are no longer standing. (Google Streetview)

Labyrinth Road isn't much in the news, nor is the labyrinth of pipes buried under our streets; until something goes wrong and water shoots out of ground in a giant geyser, a sinkhole opens up and swallows entire cars, or electric power goes out.

The most spectacular failure of all, though, is a gas leak that leads to an explosion, often combined with a devastating fire. In a city where the infrastructure generally has surpassed its intended life cycle, the idea that corroded leaky gas lines can be anywhere becomes unnerving, once one becomes aware of the destructive force of gas.  Luckily, in Park Heights whatever fire there may have initially been (some black smoke was reported) was snuffed out by the debris itself. Still, two people died and at least seven were injured, dozens were displaced from their no longer habitable homes. The full urban disaster response system, well organized in Baltimore, swung into action and remained busy all day and night to the point of exhaustion just to deal with the immediate aftermath of the explosion.

A labyrinth of gas pipes of various sizes crosses the City (SUN photo)

Natural gas travels from wellheads to consumers through a whole series of different types of pipes.

Huge new shale gas reservoirs retrieved through fracking have made gas more competitive and allowed the US to replace coal and reduce overall carbon emissions.

The country, in fact, has now so much natural gas, that a shipping facility in Calvert Cliff was retooled from import to export. 

In that case, gas would be liquefied, i.e gas under so much pressure that it is forced into a liquid state. But already, doubts about fracking and gigantic gas pipelines have reversed the fortune of this particular fossil fuel. Fracking has been banned in Maryland and elsewhere and just last month the 600-mile Atlantic Coast Pipeline has been abandoned midway through construction and after Virginia-based Dominion Energy and North Carolina-based Duke Energy had spent $3.4 billion on the project. Gas is a fossil fuel and not a green fuel. California and some other places have lately legislated gas bans that prohibit new "natural" gas hook-ups.

Pipelines, flowlines, gathering lines, transmission lines, distribution lines, and service lines, by contrast, carry gas in the gaseous state at varying rates of pressure. The higher the pressure of gas in a  gas line, the more potentially dangerous an accident with that line could be, as in the series of September 2018 Massachusetts gas fires and explosions that came from an accidentally over-pressurized line.  If local lines, not meant for high pressure, are suddenly inundated with high-pressure gas, it could result in an explosion by either the pipes themselves exploding or, more common, causing gas to leak out of pipes and valves and into homes, where it could be ignited by small sparks such as the ignition lights of the devices using gas. Rapid pressurization of normally low pressure pipes could be caused by a failure at a valve that separates high- and low-pressure pipelines or some type of human error in setting those valves. At this point, there is no indication that there was any over pressured gas pipe. More likely would be a leak from a degraded pipe that could have caused a large accumulation of gas somewhere underground or in the basement of a structure.  BGE stated late on Monday that it has found no leaks on the service lines to the destroyed buildings nor in the nearest main. BGE dates the gas lines to the 1960s. It says the lines in the area of the explosion were last inspected in July 2019. 

Nearly 4000 hazardous (dark) gas leaks (non hazardous: light blue)
reported for the BGE service area.
Source: Pipeline and Hazardous Materials Safety Administration

The network of gas lines is much like a tree with a trunk at the center and ever thinner branches at the perimeter, or like the water system with huge pipes becoming at the end just 2" or less when servicing a house. When all those pipes become obsolete at the same time, because much of the network in the core city has been installed in the same period, we have a problem. That is the problem Baltimore is facing with all infrastructure in its older sections, whether it is water, sewer or gas. Yesterday's explosion, near the Baltimore City/County line in a somewhat newer section of the city, did not involve the oldest pipes.

Baltimore gas lines leak at a high rate as the Baltimore SUN reported in an article published in September of last year. In the article  BGE Vice President of gas distribution Chris Burton is quoted attributing the dramatic increase of leakages to what he called “accelerating failure" of  ¾-inch gas delivery pipes in suburban Baltimore which were installed before the 1970s. It’s a problem in many older cities and suburbs, he said. Older gas lines were constructed with cast iron pipes that corrode over time.  Burton says that BGE is replacing about 50 miles of old pipes each year under the the 2013 mandate of the Maryland Strategic Infrastructure Development and Enhancement program, or STRIDE. BGE has set aside $963 million in a five-year plan for gas infrastructure upgrades. 

Reportedly about 1,100 miles of BGE’s 7,500 miles of gas pipes are made of old cast iron that needs to be replaced. BGE told the SUN that they receive up to 30,000 calls a year about gas odor or suspected leaks. 600 people, plus 600 contractors are assigned to gas leak detection and repair. Gas leaks can undo a lot of the initial benefit of the normally clean burning natural gas over coal. A large component of un-burned gas is methane, one of the most potent greenhouses gases, at least five times worse than CO2. Undetected methane emissions from gas lines as well as from refineries and oil wells have been recently identified as being a much larger contributor to global warming than originally estimated. 

New yellow polyethylene gas replacement pipes (STRIDE image)

The problem of leaky gas pipes has not gone unnoticed for some time. A series of explosions has punctured the general disinterest in infrastructure: Three separate episodes in Queens in killed people, in the 2010s and a half-dozen others in New York City left people injured, according to federal records dating back 10 years. Across the country, a rupture in a major pipeline in San Bruno, California in 2010 caused an explosion that killed eight people. In 2011, a leak from an 83-year-old cast-iron main in Allentown, Pa., caused a blast that killed five people according to the New York Times. In Maryland a devastating gas explosion occurred in Columbia as recent as a year ago and destroyed 22 offices.

“It’s like Russian roulette. The chances are, you are going to be lucky, but once in a while, you’re going to be unlucky.” (Robert B. Jackson, a professor of environment and energy at Stanford University who has studied gas leaks in Washington, D.C., and Boston as quoted in the NYT).

New installation and replacement lines are usually made of plastic,  more specifically semi-rigid polyethylene, supposedly a gas pipe material that can last a hundred years. That's how old some of the cast iron lines also are. It can be expected that BGE and its parent company Exelon will come under pressure to accelerate its pipe replacement program. So far consumers can be charged as much as $2 a month for the gas replacement program. Other surcharges are for green energy. It remains to be seen, how much momentum the terrible explosion  will carry into the complicated deliberations of the State Public Service Commission and whether STRIDE will be further accelerated. 

Columbia gas explosion, August 2019

Gas, water, sewer, electric networks, public transit and housing are all on the ever larger list of items where the backlog of missed maintenance and infrastructure repairs has become nearly unmanageable. That an aggressive course of action can pay off is shown by Duke Energy in Ohio, which also serves Cincinnatti. According to the NYT, beginning in 2002, Duke Energy began a 10-year, $700 million program to replace about 1,200 miles of cast-iron and bare-steel gas pipes. The number of leaks per miles for Duke Energy now ranks among the lowest in the country, the paper reports. STRIDES higher funded program anticipates full replacement of old pipes over 20 years.

The explosion In Northwest Baltimore shows once more, that the strategy of kicking the can down the road until a disaster happens is deadly and irresponsible. The responsibility rests with greedy utility companies that spend money on giant new projects instead of upkeep, politicians who prefer ribbon cutting over maintenance and with us consumers who don't want to pay the taxes and fees that are necessary to maintain a good state of repair. Of course, COVID has put us in a worse position to catch up. 

Klaus Philipsen, FAIA

The article was updated  Tuesday, 8/11/20 at 16:00h for additional information from BGE