Metam
In France, a number of incidents due to the use of plant protection products containing metam have been reported. As a soil disinfection product, it is being used at relatively large quantities per hectare. In contact with soil moisture, metam is being transformed into the gas MITC (methyle thio-isocyanate), which is the real active ingredient. The French authorities have forbidden the product following re-evaluation of the available data. In Belgium on the contrary, very strict conditions have been imposed, assuring a safe continued use of metam. Furthermore, the use of other soil disinfection products like chloropicrin or 1,3-dichloropropene could be avoided due to this authorisation. Below some more detail is given in answer to a number of questions.
- What happened in France?
- What is the situation of metam on the European level?
- What is the situation of metam in Belgium?
- What are the Belgian conditions for use?
- Who is allowed to use metam based soil disinfection products?
- Why were the authorisations for metam not withdrawn in Belgium, just like in France?
- Is the use of metam or other soil disinfection products consistent with sustainable agriculture?
- Is metam niet mutageen, kankerverwekkend of reprotoxisch?
1. What happened in France?#
In October 2018, dozens of people were intoxicated after inhaling MITC emanations. Seventeen of them had to be hospitalized for several hours. Metam-sodium has an irritating and corrosive effect on the skin, the airways and the eyes, and makes them hypersensitive. A smell of gas was observed, followed by throat irritations and eye swelling. In a few days’ time, more than 70 people were concerned.
These facts may have been caused by an improper use of a metam-sodium based product, as the French authorities indicated a non-respect of the operation recommendations “and exceptional weather circumstances, causing the soil to be too dry and too warm for a risk-free application of the product”. In Belgium, no complaints were registered like those in France.
2. What is the situation of metam on the European level?#
The active substance metam is approved in the European Union. Though it was formerly prohibited, the substance was approved again after a positive evaluation. After this approval, products based on metam were authorised in 15 EU-countries.
The approval is limited in time, as for all active substances, so the notifiers of metam have to submit a renewal application before 30/06/2019 in order to allow the competent authorities to re-evaluate the dossier for the active substance, from 30/12/2019 on.
3. What is the situation of metam in Belgium?#
In Belgium, 3 products based on metam (Solasan, Terrasan en Tamifume 690 SL) were authorised after a positive evaluation proving that their use is safe for consumers, users, workers, passers-by and people living in the neighbourhood, provided certain rules be respected in order to reduce specific risks, and provided good agricultural practice be applied (e.g. non treated buffer zones). These risk reduction measures are listed below (as well as in the authorisations, see the link per product). They are all based on scientific elements and were imposed to make sure the use is safe for the environment and for human health.
4. What are the Belgian conditions for use?#
In Belgium the authorisations for metam based products were revised in 2017 and a number of risk reducing measures were introduced in order to prevent as much as possible the propagation of MITC-gases (degradation product of metam) due to the use of metam. These measures were imposed in the authorisation documents, including the following rules for example:
- If the application is done by soil injection and the treated surface is smaller than or equal to 3 ha, a buffer zone of 20 m must be respected from homes and working places.
- If the application is done by soil injection and the treated surface is larger than 3 ha (not exceeding 5 ha), a buffer zone of 30 m must be respected from homes and working places.
- If the application is done by drip irrigation and on a treated surface of maximum 6400 m², a buffer zone of 30 m must be respected from homes and working places.
Furthermore:
- These products must not be applied at soil temperatures lower than 10°C or higher than 20°C.
- The application must be done on humid, fine-grained and well turned-over soil that is free of non-decomposed plant waste.
- Covering up the soil with a gas-tight film (TIF = Totally Impermeable Film, the highest known standard in agriculture for soil covering) is obligatory for both application types. This covering has to be maintained for 42 days after application when used in open air, and for 14 days after application when used under cover.
- When used in a greenhouse, free of plants and animals, the greenhouse has to be locked up hermetically.
- A demarcation zone of 5 m around the treated surface or greenhouse has to be respected for 14 days after application of the product: trespassing is forbidden and warning signs have to be placed.
In order to guarantee safe use, access to these products is furthermore restricted to specially trained users who have proven to know the risk reduction measures to be respected.
Thanks to the combination of the very severe risk reduction measures above, proper labelling of the products and the obligation to wear personal protection equipment and the restriction of use to trained professional users (who furthermore must hold a specialised “Ps”-type phytolicense), the risk is reduced to an acceptable level.
5. Who is allowed to use metam based soil disinfection products?#
It is very important to note that the product can only be used by professional users holding a Ps-Phytolicense “Specific professional use” allowing them to work with this active substance. A Ps-phytolicense is a license that is required in order to be allowed to work with active substances that have an increased risk. It is specific for each active substance and is only delivered after the user has passed an exam proving that the holder of the phytolicense is able to use the product in all security.
6. Why were the authorisations for metam not withdrawn in Belgium, just like in France?#
The French authorities choose towithdraw the authorisations after a new evaluation subsequent to a revision of the substance at the European level.
Taking into account the advice of the EU-authorities in favour of the approval of the substance in the European Union, as well as the decision of the Belgian Approval Committee to maintain the products on the Belgian market (provided the abovementioned severe measures be respected) there is no reason to withdraw these products from the Belgian market, as they meet all criteria to be authorised.
7. Is the use of metam or other soil disinfection products consistent with sustainable agriculture?#
In Belgium, the Regions are competent to consider potential alternatives or to substitute the use of this active substance by other phytosanitary means. As the Regions are consulted when delivering the authorisations, it was checked whether the use of metam meets the real needs of the agricultural sector.
Thanks to the authorisation of metam for soil disinfection, the renewal of emergency authorisations for two other active substances could be avoided, namely 1,3-dichloropropene and chloropicrin. These emergency authorisations from the past confirm the need of soil disinfectants.
8. Isn’t metam a mutagenic, carcinogenic or reprotoxic substance?#
Metam is not a mutagenic substance, nor a probable carcinogenic substance, nor a probable reprotoxic substance. Otherwise this substance would no longer be approved on the European level.