During the transport of hazardous materials by rail, no dangerous residues of the substance being transported may be present on the outside of tank cars or tank containers. Reports of drip leaks found on the outside of tanks have increased significantly since the fall of 2024. These drops contain substances that are environmentally hazardous and can pose a risk to people and the environment, especially if several liters of leaked substance accumulate during a journey.
In 2023 there were 26 drip leaks and in 2024 there were 52. In 2025 the number was much higher: based on reports and own observations, over 400 leaks were detected last year. Therefore, the Human Environment and Transport Inspectorate (ILT) started the Loading and Unloading project in 2025. The project focuses on improvement and prevention of drip leaks at the source.
In recent months, discussions have been held with safety services, the industry association of tank storage companies, and the chemical industry. The actual loading and unloading processes have also been observed on site, and the findings have been shared with those involved.
Valves in Closed Position
The Regulations concerning the International Carriage of Dangerous Goods by Rail (RID) contain clear provisions for inspections that must be carried out after loading or unloading tank cars or tank containers. The RID requires that it be established that valves are actually closed. To comply with the RID, terminals must create procedures that align with the provisions of the regulations. A purely visual inspection is not sufficient according to the RID.
Remediation
Arjan Grob is coordinator for hazardous substances by rail at the ILT. According to him, the reports usually involve relatively small amounts of liquid that, seemingly harmless, leak from wagons during shunting, standing, or driving. Grob: What starts with a few drops can end in an expensive remediation project or long-term environmental impact.
Economy
The ILT expects the number of drip leak reports to decrease in the coming period, partly due to the proactive efforts from the Loading and Unloading project. The sector has been reminded of the applicable rules and now knows we are very alert on this. We also expect more vigilance from tank storage companies and industry, Grob explains. He adds that the ILT keeps an eye on the purpose of the regulations, risk assessments, and proportionality during supervision and possible enforcement.
Grob: The transport of hazardous materials by rail is important for our economy. Fuels, chemical products, and industrial raw materials find their way daily through the Netherlands, over a rail network that runs through densely populated areas. This logistical lifeline also brings responsibilities directly related to the safety of people and the environment.
Continuous supervision is proven necessary by an inspection in November at a rail yard in Rotterdam. The ILT had to send back 8 of the 16 tank cars loaded with jet fuel (UN 1863) to the tank storage company. Leaks were found on several tank cars, with some gaskets being too large and not sealing properly. Agreements were made with the tank storage company to prevent this.