Frequently asked questions about DEE

Workers who inhale DEE run an increased risk of developing lung and bladder cancer. In addition, inhaling DEE can contribute to the development of serious lung diseases such as COPD and asthma. In most cases these health problems do not manifest themselves until many years after exposure.

Although exposure to DEE can also have an acute impact on a person's health in the sense of eye and respiratory tract irritations ('it's stinging my throat'), these acute effects are unreliable indicators of any long-term health risks. Acute effects occur after very high exposure to DEE (at a given point in time), while long-term risks also exist in conjunction with lower concentrations of DEE that you inhale without noticing.

Exposure can occur wherever diesel exhaust is released into the air. This may be indoors (in a shed, tunnel, ship's hold et cetera) or outdoors (for example during excavation, construction or transport operations).

In general, the closer a worker is to the source (the exhaust) and the less the air is refreshed, the higher the exposure. People may also be exposed without them even noticing.

In practice, exposure to DEE almost always occurs when working with diesel-powered equipment or vehicles. However, the degree of exposure varies.

The replacement and minimisation requirement does not apply only if an employer can demonstrate that the likelihood of exposure is practically zero. Such situations are fairly unique. One example would be that of a worker sitting in the enclosed cabin of a diesel-powered device where the air is filtered, windows cannot be opened, the engine shuts off automatically as soon as the door is opened and it is impossible for other workers to come near once the engine is running.

The legal limited value for DEE was set in 2020 and is 10 µg/m3. This limit value is a factor of 10 higher than what is normally considered to be an acceptable level of risk in the Netherlands. More information on the concept of acceptable level of risk (Dutch) can be found on the website of the Social and Economic Council (SER).

However, there is no safe limit when it comes to exposure to DEE. Any exposure to DME increases the risk of cancer and this means that the 'remove and minimise' approach always applies. Even if exposure is below the legal limit value, the employer still has a duty to eliminate or further minimise exposure where technically possible. As already mentioned, people will usually not even know that they are being exposed and in most cases health problems caused by DEE exposure will not manifest themselves until many years thereafter.

Consequently, the legal limit value only has any meaning in cases of very high exposure. If, due to (impossibilities in terms of) replacement, technical and organisational measures, exposure has still not fallen below the legal limit, exposure time must be reduced and/or personal protective equipment must be worn. The decision to wear personal protective equipment should only be taken if all else fails, as stipulated in the occupational hygiene strategy (Dutch).

Any measures taken to reduce the risks of hazardous substances in the workplace are always subject to the occupational hygiene strategy (Dutch). This strategy stipulates that measures should be taken as close to the source as possible. Removing the source (the diesel engine) is therefore the most effective way to reduce DEE exposure.

In the case of carcinogenic substances, such as DEE, the legal obligation to replace them is even more acute than in the case of other substances. The reason for this is that there is no safe level of exposure for most carcinogens (including DEE). See question 'Where might people be exposed to DEE?' under 'Health risks of exposure'.

Employers should replace their diesel devices with a healthier alternative as soon as it is technically feasible (see next question 'When is replacement technically feasible?'). Examples of replacement vehicles are an LPG-powered forklift or an electric excavator. This means employers need to stay up-to-date on the technical possibilities.

Some covenants, visions and policy documents refer to 2030 as a deadline or 'dot on the horizon' for switching to zero-emission materials and then usually in relation to environmental quality, nitrogen limitations or greenhouse gas emissions. Such forecasts can be helpful when planning investments.

Working conditions legislation stipulates that employers must always eliminate exposure to DEE, unless they demonstrate that it is not technically feasible. The available technical possibilities therefore determine whether replacement is possible. Depending on the type of device and the work situation in which it is deployed, that could be before 2030 or after 2030 - or even now.

Employers must replace carcinogenic substances as soon as that is technically feasible. 'Technically feasible' means that the facility, installation or machine is ‘operationally available and can be used in the specific situation’. If a facility is not available on the market, it will not be operationally available, for example if it only exists as a prototype somewhere in the world.

If a facility is available but, for example, only in a format that is not, or cannot be rendered, suitable in a particular use situation, the solution will not be usable in that situation. Different companies assess whether something is technically feasible in different ways. Employers must use things that are technically feasible, even if it requires customisation.

Employers will sometimes discover that it is not technically feasible to replace the diesel equipment they use, for example because no comparable non-diesel powered device is available on the market, or because business processes cannot be adapted such a way to accommodate a DEE-free device.

Employers then record the results of their research into replacement options in the risk inventory and evaluation (RI&E) to explain why the use of diesel-powered equipment to perform the work is strictly necessary and why replacing it is not technically feasible. In these instances employers will apply the next step in the occupational hygiene strategy, namely the implementation of technical measures to minimise DEE exposure.

Only technical aspects play a role in determining whether replacement is feasible or not. The Netherlands Labour Authority may ask for a written substantiation of technical arguments (in other words the employer's findings).

The occupational hygiene strategy distinguishes between 4 types of measures:

1. Replacement
   Replacing the diesel engine with a less harmful alternative.
2. Technical measures
   This means, for example, using diesel equipment with as few emissions as possible (latest Stage or European emission standards) and/or fitting a particulate filter, or using source extraction at fixed work locations.
3. Organisational measures
   These include, for example, restricting access to certain work locations, setting up and starting vehicles outside and adjusting routes to avoid vehicles or machinery getting unnecessarily close to workers.
4. Personal protective equipment
   This means, for example, wearing respiratory masks with both a gas-vapour filter and a particulate filter (type A2P3).

The occupational hygiene strategy is based on a sequential approach. For example, organisational measures will only be taken if technical measures are impossible and personal protective equipment will only be used if exposure levels have not fallen below the legal limit value thanks to the implementation of technical and organisational measures.

Emissions at source are minimal if:

• your diesel-powered road vehicle meets the latest European emission standard, or;
• your diesel-powered equipment with an output between 19 and 560 kW meets the latest Stage standard, or;
• your diesel-powered equipment is fitted with a (retrofit) particulate filter.

Diesel-powered equipment with an output <19 kW or >560 kW which meets the latest Stage standard also requires a (retrofit) particulate filter. In both cases the Stage standard is, in fact, still relatively 'broad', as a result of which machines of these 2 categories still cause relatively high DEE exposure.

Even if an employer uses diesel equipment with minimal emissions, they are still obliged to replace it whenever that is technically possible. Before investing in cleaner diesel equipment or particulate filters, employers would therefore do well to investigate to what extent replacing the equipment is an option.

There are many types of particulate filters on the market and their performance can vary greatly. In practice the Netherlands Labour Authority requires particulate filters which can reduce particulate emissions by at least 95 percent. While the current state of technology makes this possible in many cases, customisation may still be needed in specific cases. It is already common for filter system suppliers to specify the filter's effectiveness in the technical specifications.