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Chromium trioxide dossier

In June 2015, chromium trioxide was detected in old layers of paint on some of our trains. As soon as this was discovered, employees, the works council, trade unions and ISZW (formerly known as Arbeidsinspectie) were informed.


We understand that people are still worried, despite the fact that we have exercised due diligence in communication. In this dossier you can find more information about what has happened, the actions being taken within NS and what current and former employees can do.

Chromium trioxide and the health risks

In solid form, chromium trioxide is not harmful to people or the environment. Chromium trioxide is only harmful in vapour or dust form and in cases of long-term and/or frequent exposure. Our bodies can convert low levels of chromium trioxide to the harmless compound chromium (III) oxide. On the RIVM website you can find more information about what it is, its applications and what the health risks are.

The situation at NS

During standard independent research when preparing for work on the train type DDM1 at NS subsidiary NedTrain, chromium trioxide was discovered in the old layers of paint and in some components. As soon as the substance was detected, NedTrain ceased any potentially risky operations and an investigation was started in order to get a clear picture of the situation at NedTrain. At this point in time, we determined that the safety of employees was not at risk. We are conducting further investigations into the situation in the past.

Precautionary measures

NedTrain has compiled an inventory of where else chromium trioxide may be present and investigated whether the substance could be released during work activities. This revealed that chromium trioxide could be present in old layers of paint on the exterior of the following train types SGM, ICM, ICR, Mat’64, loc DDAR, DDM1, E1700 and may be present in certain fasteners in other train types. The safety regulations that are currently in use at NedTrain ensure that the risk of exposure is kept to a minimum. Employees are not exposed to levels of chromium trioxide higher than the permitted standard. In addition, new measures for improvement have been taken to reduce risks further, such as the use of new dust covers and changes to work methods.

Safety and caring for employees

As soon as the chromium trioxide had been detected, all involved colleagues, the works council, the iSZW and shortly afterwards the trade unions, were informed. We exercise due diligence and acknowledge the concerns that employees have. After all, chromium trioxide raises many emotions, especially after reports from the Ministry of Defence on the subject. Some employees and their family members are worried.

For this reason we are continuously keeping our employees informed with regards to the ongoing investigations, the possibilities for independent medical examinations (see below) and the measures for improvement that have been taken. We immediately enlisted the help of a specialised external bureau to conduct investigation into exposure to chromium trioxide on our behalf.  The RIVM is now also involved, due to their knowledge and experience in this area, and a special programme has been set up within NedTrain to look into the current and the past situation and anything else related to this issue.

Information point and signing up for an independent medical examination via the CAOP

For current and former employees (including temporary workers) of NedTrain with questions about chromium trioxide, an independent information point has been set up at the CAOP. In addition to the fact that employees can always go to their supervisors, we want people to be able to ask questions without hindrance. That is why this independent information point was set up, under the direction of the CAOP. Current and former employees who have already signed up via info@nedtrain.nl will be contacted by the CAOP.

The CAOP is an independent foundation under the supervision of the social partners and an important knowledge centre in the field of employment matters. From 2 November, the CAOP has also been handling registrations for targeted, independent medical examination.

Both current and former employees can contact the CAOP with all their questions. The information point at the CAOP is available by telephone from Monday to Friday between 9:00 and 17:00 at the following number: 070-376 54 58. You can directly register for information or medical examination on the specially set up website. You can also email COAP at infochroom6NS@caop.nl 

Or you can write a letter to:
CAOP / Informatiepunt Chroom 6 NedTrain
 Antwoordnummer 10689
2501 BW Den Haag

When is medical examination relevant?

If you have carried out any hazardous work on materials containing chromium trioxide and/or you suspect that you are suffering from symptoms, then you can register for medical examination. Medical examination cannot determine whether you have been exposed to chromium trioxide, but it is worthwhile if you have any of the symptoms mentioned below. If you suffer from any of these symptoms in the future, this offer remains open.

If chromium trioxide has damaged a person's health, they may suffer the following symptoms:

  • wounds in the nose/nose bleeds
  • rashes, ulcers or inflammation of the skin or eyes
  • impaired lung capacity of lung function

Independent testing and total transparency

NS considers it important that current and former employees can trust in all the measures that have been taken and will be taken, and that there will be total clarity with regards to present and past health risks. We do not want anything to be overlooked. That is why the chromium trioxide approach used within NS is being tested by a committee of independent experts. Precisely because employees are worried, NS wants to be totally transparent. The independent commission, which consists of a medical toxicologist, a representative of the Works Council and a representative from FNV/Bureau Beroepsiekten, was formed in December 2015 and reports on its findings and recommendations in the form of progress reports. The progress report for the period December 2015 - November 2016 will be published on this website in the near future.