1. What are SGARs?
The term “SGAR” is an acronym that stands for “Second Generation Anticoagulant Rodenticides.” As the name suggests, this class of rat poisons work by stopping the blood from coagulating (clotting) in its victim by inhibiting Vitamin K production in the body (Vitamin K is responsible for clotting the blood). This can incite a fatal reaction in animals as ingestion of SGARs can cause internal hemorrhaging. There are four chemicals registered as SGARs in the United States: brodifacoum, bromadiolone, difenacoum, and difethialone.
SGARs were created as chemical successors to first generation anticoagulant rodenticides (FGARS) such as warfarin, chlorophacinone, and diphacinone. SGARs were first developed in the 1970s because rodents were building immunity resistance to FGARs. SGARs are much more potent than FGARs as a single dose or feeding from bait containing SGARs is usually enough to kill a rat or mouse. However, it still takes days to more than a week for that rodent to die. During that time, rodents may feed from the bait multiple times. This means by the time they succumb to the poison, their system has very high amounts of SGARs in it, which can affect or even potentially kill a predator–whether wild or domestic–that consumes that rodent. This is a phenomenon known as “secondary poisoning” and it seems to be how most wildlife afflicted with SGARs poisoning get it in their systems. While SGARs were developed in the 1970s, they didn’t become more popular until the 1990s, and have steadily increased in use since the turn of the century, especially subsequent to 2015.
In 2015, the United States Environmental Protection Agency (EPA) banned SGARs from over-the-counter sales (hardware and drug stores were allowed to sell out their existing inventory until 2018) after reports were showing thousands of children across the country were accidentally eating and getting sick from SGARs every year. The current EPA regulations only allow licensed pest control professionals (PCPs) to distribute bait containing SGARs in tamper-resistant bait stations for their customers. Ironically, this seems to have led to an explosion in the use of SGARs in the Boston metro area.
2. If SGARs are not available for sale at brick and mortar stores or online, how come I still see them at stores or on Amazon?
As mentioned above, the EPA did allow stores to sell out their existing inventories of SGARs bait for several years after the ban went into effect, though they were supposed to remove whatever did not sell from their shelves by the end of 2018. If you are still seeing products containing brodifacoum, bromadiolone, difenacoum, or difethialone on store shelves, please complain to the store manager and let them know they are selling an illegal product they need to remove immediately. However, hardware stores still can legally sell most other types of rodenticides, including FGARs, as well as neurotoxins like Bromethalin.
While SGARs are not supposed to be sold to regular consumers, loopholes in SGAR laws and lack of regulatory oversight of online stores has led to the continued availability of SGARs in large quantities through websites like Amazon. This concerning (issue was chronicled in depth in a 2021 article in Audubon Magazine by Chris Sweeney https://www.audubon.org/magazine/internet-has-rat-poison-problem
3. Bait stations are tamper proof right? Meaning children and animals can’t get into the bait and it can’t get out, and the animal is trapped in there with the poisons?
No, the bait stations are not tamper proof, but “tamper-resistant,” which is very different. Broken open bait stations with exposed bait have been observed around many towns.
These poison stations do not trap an animal inside, they are designed to allow them to leave the box and pets, wildlife, or even children may come into contact with the bait that way.
Bait can also be released from the bait box and into the environment through heavy storms when waterways and areas flood, as has been studied and proven by peer review research.
During house and building fires, these poisons can potentially ignite and release toxic fumes that can adversely impact anyone who breathes it in.
One 2020 EPA report noted a 46% decline in child rodenticide incident reports related to SGARs between 2011 to 2017 and 79% between 2009 and 2018. So it does seem that child poisonings from SGARs have decreased dramatically since the EPA banned them from over the counter sales, as well as banned these poisons in pellet form and only allowed their distribution in tamper resistant bait stations. However, while these statistics indicate a substantial decline in child poisonings from SGARs, it is far from an elimination of the problem and implies that hundreds of children may still be impacted every year. Save North Andover Wildlife does not think any risk of exposure of children to SGARs is acceptable.
It finally needs to be noted that while child poisonings from SGARs have declined, child poisonings from first-generation anticoagulant rodenticides (FGARs), which are still available over the counter, have increased dramatically over the same periods of time indicated above—between 60 and 80%, respectively.
4. Are SGARs the only poison to be concerned about? What is Save North Andover’s (SNAW) position on other rat poisons?
All rodenticides pose some level of risk to non-target animals like wildlife and companion animals like cats and dogs and almost all of them also present at least some risks to people, especially children. That is why SNAW advocates for poison-free alternatives to rodent control, known as Integrated Pest Control, or Integrated Pest Management (IPM) such as improved waste management, exclusion, birth control, dry ice, deterrents, and trapping.
However, at least in part due to its sheer ubiquity, SGARs seem to be causing the most adverse environmental and public health impacts of all the rodenticides. Because of their potency–ARs (Anticoagulants) in general, and SGARs especially–seem to work up the food chain much more quickly and aggressively than other types of rat poison according to the best available research and data. Additionally, AR poisons are the most common cause of child poisonings by rodenticides. The EPA has already acknowledged the severity of these risks to children and wildlife through first-hand exposure (meaning eating the bait directly) by banning their availability over the counter. As a result, there is a strong legal precedent of restricting SGARs for advocacy groups to refer to and build on.
Most wildlife rehabilitators and veterinarians cite SGARs as the most prevalent class of rodenticides responsible for the bulk of poisoning cases of sickened or dying wildlife they admit to their practices and treat. Tufts Wildlife Clinic, a national authority on SGARs poisonings in birds of prey, has recorded trends of increased SGARs in owls, hawks, and eagles in Massachusetts (specifically, their research found 100% of Red-tailed hawks surveyed were impacted and 96% of all birds of prey surveyed overall). However, FGARs also have some pretty notable firsthand and secondary impacts on wildlife, and are quickly increasing as a primary poisoning agent of children. This is why Raptors Are the Solution recently moved to also try to add the FGAR diphacinone to the state moratorium of SGARs in California.
Unfortunately, more places are switching to Bromethalin from SGARs, which may also have unintended consequences. Likewise, more businesses and landlords are also turning to using Vitamin D bait, and while secondary impacts in wildlife are still considered relatively lower, Vitamin D bait is highly toxic to pets like cats and dogs and has been implicated in the fatal poisonings of cats and especially dogs in the northeastern region. Some studies also indicate Vitamin D bait may have some secondary impacts for dogs who eat rodents.
SNAW’s position is that Vit D. may be used as a last resort and for a limited time period by a professional pest control company, only after non-poison alternatives are fully implemented.
5. Is there a way to tell if a bait station contains SGARs and other rodenticides or not?
Sometimes. Under federal law, bait stations containing SGARs (and other federally registered rodenticides) are required to feature labels on the top that state their contents. So, if you see a bait station and want to know if it contains SGARs, look for the label on top and see if you can read it or take a photograph of it to look it up later.
Unfortunately, a loophole in the laws allow pest control professionals to forgo labeling their bait stations when the baits and bait stations are purchased or sourced separately. Even in some cases where pest companies are supposed to label their bait stations, they may not and there is limited recourse in those instances. In other cases, the text on the labels may fade or the label may peel off or disintegrate completely after being out in the elements for extended lengths of time.
If you are a tenant and believe your landlords are using SGARs but they are not being labeled, or labeled improperly, you can report your concerns to a pesticide inspector at Massachusetts Department of Agriculture. In most cases, a representative from the agency will check and if they find a problem, compel the property or pest company to properly label their products
If you are a homeowner or business owner and you contract with a pest control company and want to know exactly what product they are using in the bait stations they are placing in and around the property, you are entitled to something from the EPA called the “Material Safety Data Sheet” (MSDS) for the product they are using. This sheet will name the product and list its risks. You may also want to watch while the exterminator stocks or re-stocks the bait stations as there have been reports of pest control companies claiming to be using snap traps, but later on when the customers opened the bait stations, they found poisonous bait inside instead.
6. My pest control professional says the poison does not harm pets or wildlife, or poses minimal risks–and that only a few animals have died in the state–is that true?
No, it is simply not true that rodenticides, and especially SGARs, do not harm pets or wildlife. The risks and dangers are not only well known and documented, but serious. The EPA has conducted numerous Ecological Risk Assessments on anticoagulant rodenticides in the past 20 years and all of them concluded that the risks and impacts of ARs were significant and wide-reaching on non-target birds and mammals. The 2020 EPA Ecological Risk Assessment for Anticoagulant Rodenticides explicitly concluded: “The nature of risk to mammals and birds from ARs is well-established and includes mortality from primary and secondary exposure, as well as chronic growth and reproduction effects.” Additionally, here is an excerpted text of the Material Data Safety Sheet for SGARs: “HAZARDS TO HUMANS AND DOMESTIC ANIMALS: CAUTION. Keep away from children, domestic animals and pets…ENVIRONMENTAL HAZARDS: This product is extremely toxic to mammals and birds. Dogs, cats and other predatory and scavenging mammals and birds might be poisoned if they feed upon animals that have eaten this bait.”
It is also untrue that "only a few animals have gotten sick or died in the state of Massachusetts from SGARs". The veterinary wildlife hospital and rehabilitation clinic, New England Wildlife Center, sees close to 200 wildlife patients a year exhibiting tell-tale signs of SGARs poisoning (namely, their blood is not clotting). And that is just one wildlife clinic in one part of the state. Unfortunately the only evidence the state or federal government will usually admit to confirm SGARs poisoning is a liver necropsy (autopsy) of a dead animal. But the state government usually only tests animals that are listed under the federal or state endangered species lists. Since 2021, three bald eagles have died due to SGARs in Massachusetts, but those are just the ones found and formally tested. Many other animals are not necropsied and simply disposed of because of costs (necropsies are expensive and many wildlife rehabbers run on shoestring budgets).
Meanwhile, fundraising efforts by concerned citizens collaborating with local veterinarians have funded independent necropsies at approved laboratories of a number of dead wildlife discovered in the past year in the Boston metro area–and ALL were found to have high levels of toxic SGAR poisoning. This included a Great Horned owl, a Barred owl, a Cooper’s hawk, and a Red fox. Imagine how much greater the number of confirmed SGARs in wildlife would be if the state or federal government actually invested funding in mandatory testing of dead wildlife suspected of SGARs poisoning?
If a pest control professional tells you that SGARs do not pose any or minimal lethal risks or dangers to your pets or wildlife, they are either not being honest or they are untrained in the facts.
7. How come pest control companies have told me/my family/my friends/my neighbors that SGARs and other rodenticides are relatively harmless to other animals besides rodents?
It may be that the pest control professional is uninformed about the risk of their products. But there doesn’t seem to be any legal obligations for pest control professionals to disclose the risks of SGARs and other rat poisons to people and non-target animals like pets and wildlife, even when directly asked about it. In fact, it looks like they can even go out of their way to evade the truth and still avoid legal accountability. According to an email from an EPA representative “…it is not a violation under [federal law] for pest control professionals to make inaccurate claims about the impact of SGARs on non-target animals, as long as they are not putting a false label on a bait station.” The state could intervene and impose tougher transparency laws and policies compelling pest control professionals to acknowledge and disclose the risks of SGARs and other rat poisons to the public, but so far Massachusetts has not taken any such action.
A proposed state law, informally known as the “Hawkins bill” initially contained language that would have required pest control companies to disclose the risks to wildlife and pets that SGARs pose to potential clients and require customers to sign a form with this information attesting they have been notified of the risks–before the company could apply SGARs on their property. But (not surprisingly, considering the influence of the pest control lobby on our political bodies), it was stripped from the bill when it made it to the Senate. Subsequent iterations of the bill have not included this provision.
The pest control industry reaps significant financial benefits from public dependency on SGARs (and other rat poisons). So it makes sense that they would not volunteer information that would prejudice people against their products and adversely affect their bottom lines. This creates a perverse incentive for pest control professionals to mislead people in order to continue to turn a profit. SGARs are usually sold on a subscription-based model and often account for a significant percentage of pest company’s profit margins. Keeping people “hooked” on SGARs means muddying the truth so people don’t feel guilty or opt for more humane and environmentally-friendly methods of rodent management.
8. As much as I don’t want to hurt other animals or children by using poisons, rats are a huge public health problem that spread diseases (like the Black Plague), so doesn’t giving up SGARs and other rodenticides mean we will get more rat-borne diseases?
While it is certainly true that rats can spread diseases and pose valid public health risks, pest control companies tend to greatly overstate those risks, even to the point of trying to sow panic over rats and mice when it isn’t warranted by data.
Despite considerable upticks in the presence of rodents in metro areas and the suburbs in recent years, reports of disease transmission between rats and humans remain remarkably low–often numbering in the single or low double digits in the state over the course of a year. In other words, statistically speaking, it seems a child in many instances is much more likely to be poisoned by rodenticide than sickened by exposure to a rat. A child or adult is also significantly more likely to get bitten by a dog (by hundreds of times) than bitten by a rat. Additionally, there are many diseases rats and mice do not spread, like rabies, that are actually pressing public health threats, yet we are not raining down lethal methods on rabies vector species like raccoons and foxes.
Even diseases that pest control representatives often refer to in justifying their rampant use of SGARs–like the Black Plague pandemic that killed millions in the Middle Ages–is now widely believed by experts to actually have been caused by a combination of gerbils (yes, gerbils) and human-specific fleas–in other words, not rats. While rats can potentially carry plague, it is somewhat rare and transmission to a human is even rarer.
Moreover, a recent study found that rats that have ARs in their systems are much more likely to carry and transmit certain zoonotic diseases to humans, like Leptospirosis. This makes sense since SGARs lowers the immune systems of rats that consume them, making them more susceptible to disease.
Rats that have SGARs or other poisons in their systems also act sluggish and disoriented. They are much more likely to come out in public spaces in broad daylight, including in areas with high foot traffic frequented by dogs and children. This makes human contact with a poisoned rat more rather than less likely. A child or pet may accidentally step on a sickened rat or even mistake it for a toy and touch it. By comparison, a healthy rat will often go out of its way to avoid people and pets. There are many anecdotes and recorded footage and photographs taken around our area of dying rats exhibiting signs of SGARs poisoning crawling around crowded public areas in the middle of the day with a lot of people walking around, like this video (one of several of similar incidents recorded) by Save Arlington Wildlife founder Laura Kiesel.
Finally, when a rat dies of SGARs, the parasites on them like fleas or ticks (which carry Lyme disease), will leave their body and search for a new host. If you have bait boxes drawing rats onto your property, then those parasites are now in close proximity to you, your children, and your pets. This is all to say, if you are worried about disease transmission or parasites from rats–the data strongly suggests SGARs are more likely to make that a problem than abate it.
9. My pest control company/landlord/local health official told me poisons/SGARs (or other poisons) are the best/most effective ways to control rats and mice and if we stop using rodenticides we will be drowning in rats. Is that true?
Answer: First and most importantly, there is no comprehensive peer review data that we have been able to find (and we have looked high and low) that shows SGARs meaningfully reduce rodent populations in urban and ex-urban/suburban areas, or that they reduce rodent populations meaningfully over the long-term. In other words, claims that SGARs are the most effective way to control rats don’t seem to be backed up by any actual research or genuine data. In fact, both the EPA and USDA specifically recommend short-term and limited use of SGARs in part because it can cause more problems than it solves.
Furthermore, some studies and trends seem to indicate that the extensive and widespread use of SGARs may actually be increasing rodent populations or causing infestations where they didn’t previously exist. Think about it: Despite the fact that SGARs use in the Boston metro area has exploded in the past decade, reports of rat sightings and activity have actually increased in tandem with that rise of SGARs use instead of going down. If SGARs are so effective at reining in rodents, why is our collective problem with rats getting worse instead of better when we have SGAR bait boxes in almost every block in city and town centers? Rat populations can become more prevalent for a number of reasons including warmer winters (which lengthen their reproductive cycles), construction (which disrupts their burrows and forces them into confrontations/conflict with people), and increased human density and with it, waste, and poison. Here are some reasons why poison can make the problem worse.
Baits act as a lure. So if you have out bait all the time, you are essentially leaving out a food source for rodents 24/7, which actually attracts them to the area. Not all the rodents drawn to the bait will eat it, as some will decide it is not appealing enough. They then will focus on finding more preferable food sources, like those found in your trash cans, yard, or even inside your home. Other rats may actually suspect the bait is poisonous, and not only avoid it, but might even be able to communicate warnings about it to other rats. Rats are highly intelligent and can make conclusions based on the experiences they or their kin have. So if a bait makes them sick, or a family member dies after eating a lot of it, they may be able to remember that experience and adapt their behavior accordingly by avoiding that or similar “foods.” The phenomenon even has a name: “bait shyness.”
For those rats that do eat the poison, they can build biological resistance to the poison, similar to antibiotic resistance. Remember how SGARs were developed because FGARs stopped working as well on rats and mice? That is because many rodents developed an immunity to FGARs. Now studies show the same thing is happening with SGARs. Rats and mice breed A LOT. A single female rat can have hundreds of offspring in just one year. When you breed that fast/much, you can build biological resistance to certain diseases or chemicals better than creatures with slower/lower reproduction rates. Simply put: rats can outbreed any poison but their predators can’t.
9. Why are predators a better solution than anticoagulant rodenticides?
Starving and exclusion, as outlined in question #10, should be the first order of business in rodent control. Beyond these crucial methods, predators are probably the single greatest defense we have against rodents, but we are failing them by poisoning their prey. Predators, especially birds of prey, are designed to and have evolved over millions of years to hunt and eat rats and mice. A single Great Horned Owl can kill upwards of 1,500 rats (or as many as 4,000 mice) in just one year’s time. If you kill off that Great Horned Owl by poisoning its prey, you have now removed that rodent controller from the ecosystem and many (if not most) of the 1,500 rats it would take over the year will probably stay in the environment and live on to have babies. When you kill off nearly an entire family of Great Horned Owls from poison, as happened at Menotomy Rocks Park in Arlington in 2022, you have ensured thousands more rats will remain in that neighborhood and likely reproduce. Unlike stationary poisons in detectable bait boxes, rats cannot learn to just avoid predators, nor can they build biological resistance to them. Again, this is not conjecture, as a peer review study found hawks and owls are significantly more effective at controlling rodents than anticoagulant rodenticides.
Unlike rats and mice, raptor species like owls, hawks, and eagles only breed once a year and only have an average of two to four young. So it is very easy to eradicate a whole nest due to SGAR poisoning and effectively extirpate that species from the immediate area or locale. For example, the subsequent deaths of eagles in Arlington - C25 and MK from SGARs poisoning - led to the departure of MK’s surviving mate, KZ.gAnd in doing all of this, we have ironically created more optimal conditions for the rat population to boom.
There are also unfortunate behavioral impacts on humans that the widespread availability of poisons seem to have had, that likely encourages and sustains rat infestations. Many times over-reliance on poisons fosters complacency about rodent management. In other words, instead of a business cleaning up a dumpster, or a landlord sealing up holes and gaps in their tenant building/s, or a homeowner removing their birdfeeders or outdoor compost bin, they will resort to putting poison down and be done with it.
While putting down poisons may be cheaper or quicker in the short run, it does not solve the problem in the long run. The rodents will be even more drawn to the area because of the trash AND the poison (which again, is a food source for them) and then likely choose the tasty trash, birdseed, or compost you left out over the bright off-putting poisoned bait. And who can blame them? Of course, most pest control companies aren’t going to tell you to address these other problems if you really want to get rid of rats, because they want you to keep having rats as a problem, so they can keep stocking those bait stations with more poison and making a perpetual profit.
Finally, places that have established moratoriums on SGARs like California and British Columbia, are not suffering from rat infestations. So don’t fall for the hype pest control companies are pushing.
10. So if poisons don’t help and potentially make rat problems worse, what are some alternatives?
Integrated Pest Management (IPM) is a combination of strategies that modify the environment and make it less attractive for rodents (Himsworth et al., 2012). Environmental modification can be broken down into three steps:
11. If SGARs are so dangerous, why don’t towns or cities just ban them? Why hasn’t the state or EPA banned them? Doesn’t legal mean safe?
Massachusetts’ law prevents municipalities from banning or restricting ANY pesticides used on private property, including rodenticides like SGARs. This is known as “preemption” and the pest control lobby depends on it to ensure their businesses can keep using the chemicals they do. The National Pest Management Association even wrote regarding preemption that:
“Regulating pesticides at the state-level is a fundamental pillar to the success of the structural pest management industry…. In states that prevent local governments from regulating pesticides, our industry must mount an impenetrable defense of existing state law, as activists relentlessly attempt to chip away at pesticide preemption laws in state legislatures.”
Any town or city that wants to ban SGARs in Massachusetts has to ask the state for permission by submitting what is known as a “Home Rule Petition.” Despite that the law only relates to the municipality that submits it, the Home Rule Petition has to be voted on by the entire state legislature.
As for SGARs not being banned on the state level, the New England Pest Management Association has a very strong lobbying presence in Massachusetts. Massachusetts is notorious as being one of the most difficult to pass laws on the state level and has been described as having one of the most convoluted legislative processes in the nation.
Regarding the EPA, as noted in the Question #1, the EPA encountered a lengthy and costly lawsuit by the pest industry when they merely attempted the relatively conservative move of banning SGARs from over the counter sales in response to child poisonings. If the bar is so low for child safety, how can we expect it to be even higher for the safety of our pets and wildlife unless the public begins demanding it? In the meantime, the pest control lobby wields enormous influence at all levels of government and at their respective agencies. Additionally, the EPA in recent years has had their funding slashed, particularly in their regulatory divisions tasked with analyzing the safety of pesticides and chemicals–while the agency also retains a revolving door with the pest industry (meaning many staffers at the agency actually are likely in favor of these industries).
Finally, it is just a truth that what is legal is not necessarily safe. DDT was legal for many decades before it was permanently banned in the US. That effort took overwhelming public pressure and outcry over the course of a decade to achieve. By the time DDT was banned, many species were at the brink of extinction, including the Bald Eagle and Peregrine Falcon. Even more recently, as evidenced by SGARs, it was allowed to be sold in brick and mortar stores as loose pellets for years even as the pest control industry and EPA were well aware that thousands of children were being poisoned by them every year.
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