Fumigation. Possibly one of the most complex aspects of pest control, and something that if not done safely and in line with relevant legislation can have lethal consequences. We spent some time chatting to Faldie van Wyk, Rentokil South Africa's Fumigation Manager, about this important topic.
What does fumigation involve, and when is it used?
According to Faldie, the very term itself is widely misunderstood. The general public often refer to a spray treatment or a self releasing aerosol treatment as fumigation; using it in the wrong context. At Rentokil we get customers phoning us and asking if we can fumigate their homes, however the term ¨"fumigation" is defined as 'inserting a lethal dosage of gas into a closed vessel'.
Fumigation is most typically done for products that have - or may have - a pest inside the product itself, such as wood borer, tobacco beetle or any other stored product insect. In fact - according to Faldie - the golden question when evaluating a fumigation job, is "Is the pest inside or outside the product?" If the pest is inside the product, then it has to be fumigated using either Methyl Bromide or Phosphine. says Faldie.
These gases permeate the product and kill all insect life stages; egg , larvae nymph and adult. If the pest is outside the product, then we look at alternatives such as fogging and Ultra Low Volume (ULV treatments). When the pest is both inside and outside the product, we look at a combination of fumigation and fogging or ULV to ensure we completely eradicate the problem.
At present, there are only 2 gases commonly in use for fumigation: Methyl Bromide or Phosphine. However, the Department of Agriculture is currently phasing out the use of Methyl Bromide. Methyl Bromide may only be used to fumigate quarantined items (items waiting at the airport or port to come into South Africa), and items that are exported and require an ISPM15 stamp. Anything else that requires fumigation has to be done with using Phosphine, or a Heat treatment, as there are no other acceptable alternative chemicals.
Self releasing aerosols - which less reputable companies may try and pass off as fumigation - cannot eliminate a pest that is inside a product and are better suited for scenarios where the pest is external, like a cockroach infestation.
It is important to note, says Faldie, that each of these treatments can only be done in specific circumstances. Both Methyl Bromide and Phosphine are gasses, and therefore react with certain products. For example, you cannot use Methyl Bromide on anything that contains rubber, so fumigating a car (for example) is out of the question. The gas stays within the rubber and will leave a terrible smell. Phosphine on the other hand cannot be used on metal or wire as it corrodes over time. Methyl Bromide fumigation has a 24 hour turnaround time, whilst Phosphine takes much longer; around 5-7 days for a container.
Who can perform a fumigation service?
Only companies registered with the Department of Agriculture are legally allowed to perform fumigation services. The Company technicians also have to be qualified to perform a fumigation service; this means they have a current P number, and have had specific training in fumigation. The reason for this is that fumigation - if done incorrectly - can be deadly, and there are very strict health and safety standards that need to be adhered to in order to ensure the safety of both the technician and the customer.
Because exposure to even a very small amount of Methyl Bromide or Phosphine is lethal and can result in death, equipment must be finely calibrated to give you very accurate readings of the levels of gas in the container at 2 hours, 4 hours and 24 hours in order for certification. This safety equipment is extremely expensive, and something that smaller, less reputable providers may not be able to afford. Fly by nights have no regard for safety¨, says Faldie. You have to remember that you are working with lethal amounts of gas in an enclosed area. A reputable fumigation company will have not only qualified, experienced staff with the correct safety equipment and PPE, but also public liability insurance and accurate gas measurement tools.
We are often asked why fumigation is so expensive. The answer to this is that not only is the gas extremely expensive, but accurate measurement tools are also extremely expensive. This means that many of the smaller businesses can't afford to invest in these tools. They may be able to offer a more competitive quote because of it, but the risk of not measuring properly is huge. An entire shipment could get sent back because the fumigation did not meet the required standards, resulting in huge revenue loss, not to mention the loss of reputation.
What about Fumigation in Transit (FIT)?
Rentokil currently offers container fumigation, stack fumigation, and silo fumigation, says Faldie. Fumigation in Transit is when a container is filled with fumigant gas in one area, then loaded onto a truck or boat and sent to either another part of the country, or overseas. The container is then only opened up again when it reaches its destination.
Rentokil does not offer fumigation in transit as - whilst it is not legally prohibited - Rentokil globally has taken the stance that it is an unsafe practice. As you can imagine, there is no way of doing all the required safety checks at the required intervals to establish the levels of gas in the container at 2 hours, 4 hours and 24 hours, and these containers therefore pose a huge risk to the individual opening them when they reach their destination.
As accurate gas readings are also a requirement for certification, it means we can't offer a certification in good conscience. The only exception to this is containers that go cross-country and can be opened up at a Rentokil branch on arrival, where the relevant safety checks and readings can be performed by a fully qualified Rentokil technician, equipped with the appropriate PPE and safety equipment.
Some fumigation terminology explained:
ULV: Ultra low volume treatments: pesticide is dispersed in smaller molecules than a conventional spray treatment, and can therefore penetrate cracks and crevices that the spray treatment can't access. It's important to note that it's not a gas; it is still a pesticide spray that leaves a residue. ULV treatments are best suited for crawling and flying insects.
Fogging: Pesticide exits machine as a smoke, and can therefore penetrate cracks and crevices that the spray treatment can't access. Unlike a ULV treatment, fogging doesn't leave a residue, and is therefore only effective against the adult life cycle of the insect. Fogging treatments are best suited for Flying insects.
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