Aging gas line in Utrecht blast area was scheduled for replacement by 2028
A gas pipeline beneath Visscherssteeg in central Utrecht, where a powerful explosion and fire caused extensive damage on Thursday, was more than 30 years old and was scheduled to be replaced within the next two years, according to grid operator Stedin.
The explosion, believed to have been caused by a gas leak, has renewed concerns about the safety of aging gray cast-iron gas pipelines that are still in use in parts of the Netherlands. What exactly caused the blast in Utrecht is still under investigation.
According to AD, maps published by Stedin show that the gas line running through Visscherssteeg consists of gray cast iron, a material widely used in the Netherlands for gas infrastructure since the early 20th century. Under national regulations, all gray cast-iron gas pipes must be replaced by 2030. Stedin indicated that the pipeline in Visscherssteeg was expected to be renewed before 2028. Authorities have not yet determined whether the outdated pipeline played a role in Thursday’s explosion.
Similar incidents involving gray cast-iron gas lines have occurred before. In January 2019, a 12-centimeter crack formed in a cast-iron gas pipe in the Jan van der Heijdenstraat in the Laak district of The Hague. About 10 cubic meters of gas leaked into the crawl space beneath a three-story apartment complex. The volume was too small to be detected by the grid operator, allowing gas to accumulate and trigger a massive explosion. The building was so severely damaged that it was later demolished. Three members of one family were seriously injured.
A comparable failure occurred in 2008 in Amsterdam, when a gray cast-iron main gas line ruptured near the Haarlemmer Houttuinen, destroying storage units in an apartment complex.
Concerns about the safety of such pipelines had already been raised earlier, including after a 2002 accident in Amsterdam’s Czaar Peterstraat. Investigations showed that cast-iron pipes are vulnerable to bending caused by soil subsidence and can break as a result. Although these risks had been known for decades, the use of cast iron for gas pipelines was not banned until 1994.
The 2008 Amsterdam incident prompted an accelerated national replacement program. At that time, about 6,519 kilometers of gray cast-iron pipelines remained in the ground, out of a total gas network of approximately 125,300 kilometers. Replacement initially focused on high-risk locations, based on factors such as soil conditions, pipe age and local circumstances, including subsidence, heavy traffic and construction activity.
After the 2019 explosion in The Hague, authorities found that about 3,025 kilometers of cast-iron gas lines were still in use, mainly in the Randstad, where Stedin, Liander and Enexis operate the networks.
The replacement program was accelerated again, and the State Supervision of Mines granted grid operators until 2030 to replace all remaining cast-iron pipes with safer steel and plastic alternatives.
Regulators also required more frequent inspections using sensitive detection equipment. In densely populated high-risk areas, checks must be carried out daily, while lower-risk areas must be inspected at least once a year.
