Pesticides are approved in two distinct stages. Firstly, the active substance – the chemically active part of a manufactured pesticide product – is authorised. For the second stage, pesticide products containing that active substance (usually alongside many other ingredients known as ‘co-formulants’) are authorised. For example, the active substance glyphosate had to be approved before it could be allowed to be sold in the pesticide product ‘Roundup’. With that in mind, this is what the classifications in the table above mean:

• Banned – Many pesticide active substances and products are approved but then subsequently found to be negatively impacting human health or the environment once in use, leading to approval being rescinded. There are numerous examples of this happening, perhaps most famously with DDT.
• Never approved – Not all pesticide active substances are submitted for approval in every country. This can be for any number of reasons including; unsuitability for the specific conditions in that country such as landscape, crops or weather, marketing issues or because the pesticide will not meet the regulatory requirements for the administrative region, including the accepted level of threshold for harm.
• No products ever approved – Even when a pesticide active substance is approved for use, a country may choose not to approve any products that contain it due to concerns about its suitability for that particular area or the harms it causes.

• ‘Highly toxic to bees’ – This classification is assigned if the LD50 (lethal dose 50%) for acute and dermal absorption by honey bees is lower than 2 micrograms per bee (μg/bee).  The value of LD50 for a substance is the dose required to kill half the members of a tested population after a specified test duration. A lower LD50 is indicative of increased toxicity as it shows that it takes less of a substance to kill half the population.
• ‘Groundwater contaminant’ – Strict limits are set for pesticides in groundwater due to the potential for them to negatively impact drinking water quality and aquatic ecosystems. In order to maintain the integrity of groundwater sources, a precautionary limit of 1µg/L is set for pesticides. Some pesticides regularly exceed this limit and are therefore classified as groundwater contaminants.
• ‘Endocrine disruptor’ – Interferes with hormone systems and can cause birth defects, developmental disorders and reproductive problems such as infertility.
• ‘Carcinogen’ – Capable of causing different types of cancer, including leukaemia and non-Hodgkin’s lymphoma.

It is important to note that if a substance is classified as a ‘carcinogen’ (for example) it does not mean that exposure to it will definitely result in the development of cancer. The classification simply means that in tests for toxicity the substance can cause a particular effect.

Companies that manufacture pesticides are required by national regulators (such as the European Food Safety Authority, US Environmental Protection Agency and UK Health and Safety Executive) to conduct toxicity testing as a key part of the process through which an active substance is approved.  The data generated by this toxicity testing is fed into risk assessments which are then used to determine the extent and nature of the potential harm an active substance poses to human health and the environment.  When we say an active substance is a ‘water contaminant’ or ‘carcinogen’, it is based on the results of these national risk assessments.

There are a number of databases that collate this toxicity data and regulatory decisions from around the world. To ascertain the impacts of the five active substances listed above, PAN UK used the following two sources:

• University of Hertfordshire Pesticide Properties DataBase
• PesticideInfo database (managed by PAN North America)

While voluntary and stewardship approaches may work in other areas, they have repeatedly proven to be ineffective at reducing pesticide-related harms to either human health or the environment for a number of key reasons, including:

Hazard vs. risk-based approaches – Arguably the most fundamental problem with voluntary and/or stewardship approaches to reducing pesticide harms is that nothing is as effective as removing the hazard itself. The UK (along with the EU) currently follows what is commonly called the ‘hazard-based’ approach to pesticide regulation. This means that if an active substance is judged to be intrinsically dangerous – for instance by being able to cause cancer or persistent pollution – then it is too hazardous to be used safely and should be banned. Controlling exposure to hazards is a basic approach to protecting workers and the environment which is applied far beyond pesticides. The fundamental principle underpinning risk management in hazardous industries such as construction and nuclear power is that the first step is to “eliminate the hazard”. Only if this is impossible, should other means of controlling the risk be considered.

The ‘risk-based’ approach sits in direct contrast. It emphasises assessing and managing risks and involves the deployment of specific measures to keep risks below acceptable levels.

To apply these two approaches to veterinary medicines, a hazard-based approach might see the most environmentally harmful active substances banned from appearing in medicines, while a risk-based approach would recommend that owners do not let their pets swim in rivers for a certain length of time after applying a spot treatment.  It should be noted that, if the UK implemented the hazard-based approach to its full extent, then active substances deemed to be too harmful to be used on crops would also be banned in veterinary medicines.

Use reduction vs. risk reduction – Another key reason that voluntary approaches don’t work is that they almost always focus on reducing the risks associated to pesticides, rather than reducing the amount of pesticides being used. While ‘use’ is easy to quantify and measure, ‘risk’ is not. By focussing on risk, voluntary approaches manage to block any meaningful action which would reduce the amount of pesticides applied. It sounds obvious, but evidence from around the world shows time and time again that the best way to meet the ultimate goal of reducing harms is to reduce the amount we are using. Or in the case of Highly Hazardous Pesticides, introduce bans to eliminate the hazard all together.

There are many examples of voluntary schemes on pesticides failing. Meanwhile, the body of evidence on the environmental harms caused by pesticide active substances found in medicines for cats and dogs has been growing for more than five years now. Despite many statements of concern from both veterinary and environmental groups over the years, concrete improvements or reductions in use have not occurred. PAN UK and its allies, therefore, believe that it is time to adopt a precautionary, hazard-based approach and ban the pesticide active substances from being included in pet medicines.

An ectoparaciticide is an antiparasitic drug (usually a ‘spot-on’ treatment) used to kill parasites that live on the body’s surface (such as ticks and fleas). In the UK, there are 676 ectoparaciticide products approved for use in veterinary medicines for dogs and cats. Of this total, 523 products (77%) contain one or more of the five active substances listed above.

An endectocide is an antiparasitic drug (usually in tablet form) used to kill parasites that live both inside the body (such as worms) and on the body’s surface (such as fleas). In the UK, there are 218 endectocide products approved for use in veterinary medicines for dogs and cats. Of this total, 58 products (26.6%) contain the neonicotinoid imidacloprid and/or fipronil, which are two of the active substances listed in the table above. None of the other three active substance listed above are included in any endectocides approved for use as a medicine on dogs and cats in the UK.

PAN UK’s 30+ years of expertise is on pesticides used on agricultural crops (or ‘plant protection products’ as they are also known). Therefore, we came to the issue of veterinary medicines with this background and so began our research by looking at active substances that are not approved for use on agricultural crops due to the harms they cause, but are permitted for inclusion in veterinary medicines. We were trying to understand how chemicals such as fipronil and imidacloprid could still be present in UK rivers, despite no longer being used on crops.

This approach led us to a list of nine active substances that are not permitted for use on agricultural crops but are used in veterinary medicines. Of the nine:

• One is approved for use on cattle and sheep (alpha-cypermethrin)
• One is approved for use on honey bees (amitraz)
• One is approved for use on rabbits (cyromazine)
• One is approved for use on salmon (teflubenzuron)
• Five are approved for use on cats and dogs (dinotefuran, fipronil, imidacloprid, nitenpyram and permethrin)

Due to the prevalence of active substances included in medicines for cats and dogs, we decided to focus solely on those species. We had thought that we might include rabbits under a broader heading of ‘pets’ but discovered that, while banning the five active substances in question would leave plenty of alternative products for dogs and cats, this would not be the case if cyromazine was banned for rabbits and so we removed them from the project.

In addition, given that anything to do with livestock links directly to issues around farmers’ livelihoods (and the fact that many British farmers are struggling to make ends meet right now) an initial focus on cats and dogs also feels like an appropriate place to start, since the risks undertaken by those in the agricultural sector arguably outweigh those taken by pet owners.

They are by far the most common animals kept as pets in the UK, with 10.2 million dogs and 11.1 million cats. According to the PDSA, 80% of UK dogs and 82% of cats are treated with parasiticides (more commonly known as tick and flea treatments). Dogs and cats therefore represent a large percentage of the total amount of these products used on UK pets.

Banning the five active substances in question from appearing in medicines for dogs and cats could potentially have a significant impact in terms of preventing environmental harms. As mentioned above, there would still be plenty of alternative medicines available.

Many of the other chemicals used in tick in flea treatments are known to be harmful to human health or the environment.  They are, after all, designed to kill living organisms and therefore need to cause harm – at least to the target species – in order to be effective.

By focusing on banning pesticide active substances from inclusion in pet medicines, we are not saying that alternative treatments are safe or even necessarily less harmful. There is so little research out there that, in reality, we simply do not understand the true impacts that the chemicals contained in pet medicines are having on health or environment. We certainly need more research to be conducted in this area, but this should not be a reason for inaction. In fact, this scientific uncertainty is exactly why UK pesticide regulation is underpinned by the precautionary principle which allows regulators to adopt precautionary measures when scientific evidence about an environmental or human health hazard is uncertain and the stakes are high. Under the precautionary principle, regulators do not have to wait for the evidence of harms to be definitive, an often-unattainable goal.

This is why we have focused on banning pesticide active substances known to cause harm. These five chemicals have been through the regulatory system and deemed too harmful for use on crops. It simply makes no sense to allow them to be routinely applied by millions of pet owners every month. If we want to tackle chemical pollution, then we urgently need to take a more holistic approach and close this loophole. Where alternatives exist, which they absolutely do in the case of pet medicines, chemicals known to be harming wildlife should be taken off the market. Meanwhile, the government and others should fund research into less-toxic, and ideally non-chemical, alternatives so that pet owners can rest assured that they are not driving pesticide-related harms to health or environment.

There are currently more than 1,000 parasiticide products for cats and dogs in the UK. While a ban on pesticide active substance being included in pet medicines would mean removing 67% of these from the market, it would still leave almost 350 alternative products available.

The list of alternative products includes spot-on treatments, sprays, gels, treated collars and tablets so owners would continue to have a wide range of choice in terms of how they apply parasiticides to their pet. While the majority of alternative products are prescription only, there would still be products available for owners wanting to buy medicines over the counter or online.

The cost of parasiticide products vary greatly. However, those containing pesticide active substances tend to be roughly comparable with the alternatives in terms of price so a ban should not affect pet owners struggling with the cost of living. It can be argued, in fact, that many pet owners are spending money unnecessarily by treating their pet for parasites every month regardless of whether an infestation has taken place. Pet owners struggling with costs could consider stopping prophylactic use and instead monitoring their pet closely for parasites and only treating if necessary.