Hague gas explosion shows cast iron pipelines pose national risk: report

Dutch emergency services in action
Dutch emergency services in action. (Photo: Dolfilms/DepositPhotos)

A large gas explosion in The Hague in January shows that cast iron gas pipelines pose a risk to the entire Netherlands, the state supervision on mines SodM concluded after investigating the explosion in the crawl space of the Hague apartment building. There are still 3,830 kilometers of dangerous gas pipelines in the Netherlands, and network operators must remove and replace these pipelines more quickly, the SodM said, NOS reports.

The explosion on Jan van der Heijdenstraat completely destroyed three apartments. Nine people were injured. One man was stuck under the rubble for eight hours before being rescued. He had to undergo surgery on both his legs. The fire department called it a miracle that no one died. 

The blast was caused by a crack in a gray cast iron gas pipe. This material was widely used in underground pipelines until 1980 because it was relatively cheap and easy to work with. Cast iron is known as strong, but brittle - subsiding soil and vibrations due to construction work can cause the pipes to break. The laying of new cast iron pipes was therefore banned in the Netherlands in 1994. PVC and steel are now the norm.

Leakages from brittle cast iron gas pipes also caused serious explosions in Amsterdam in 2001 and 2008, also leaving many people injured. The Dutch Safety Board and its predecessor then concluded that the pipes "represent an uncontrollable risk for citizens", according to NOS. In 2010 an official removal program was finally implemented, during which unsafe pipes made of asbestos cement are also removed. More than half of the hazardous pipes have now been replaced. Some 2.5 percent of the gas pipelines in the Netherlands are still made of cast iron. 

The SodM now concluded that this removal program, which is set to be completed in 2029, is not happening fast enough. The regulator calls on network operators to speed it up. 

The SodM also concluded the risk classification for cast-iron pipes needs to be rethought. The explosion in The Hague showed that cast iron pipes with a risk indication of 'low' or 'medium' are also potentially dangerous. The pipes in Jan van der Heijdenstraat were classified in the lowest risk category. The SodM recommends conducting more research into the influence of aging, vibration and soil density on cast iron pipes. 

The regulator also called on Hague network operator Stedin to adhere better to risk classifications. In the past years, Stedin gave priority to pipelines that could easily be removed due to other construction projects. This 'piggyback' resulted in hazardous pipes being removed later than less hazardous ones. Stedin was supposed to have all its high-risk pipes removed by 2016, but there are still some 4 kilometers of hazardous pipes in the ground. Stedin is also generally behind with the removal, removing and replacing pipes more slowly than the other network operators, SodM said.

Stedin will respond to the SodM's findings after the official publication of the report, according to NOS.

With regards to the SodM calling on network operators to speed up the removal program, industry association Netbeheer Nederland told the broadcaster on behalf of the network operators that "replacing a few thousand kilometers of gas pipelines takes time and is going according to plan". Leaks are "exceptional" and the number of incidents has decreased, the association said. Netbeheer Nederland added that it is open to measures, including speeding up the removal and replacement program. 

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