The Berkey manufacturer has filed a lawsuit against the EPA seeking to stop it's unjustified persecution of Berkey Water Filters based on the EPA’s decision this year to treat Berkey Water Filters as though they are pesticides, rather than water filters. The EPA has already ordered the closure of Berkey's largest warehouse. Please see our blog post for the details.

Berkey Water Filters Sues the EPA

March 13, 2024 Berkey Files Additional Suit Against EPA in Federal Court

March 6, 2024 – Berkey International has filed a lawsuit against the Environmental Protection Agency (EPA) for misclassifying Berkey Water Filters as pesticides, and is seeking an injunction to lift the EPA’s Stop-Sale orders (SSURO) issued to NMCL dealers, vendors, and Berkey International’s manufacturing facility located in San Juan, Puerto Rico.

Berkey International supplies Berkey® Water Systems to New Millennium Concepts, Ltd (NMCL). NMCL is the sole wholesale distributor of Berkey® Water Systems globally. The Stop-Sale order (SSURO) placed on this facility by the EPA has tied up significant inventory and resources needed to meet the demand of Berkey® customers throughout the world and has created a shortage of Berkey® water systems and products globally.

This lawsuit is in addition to a third-party lawsuit filed in the North Texas District Court in August 2023 by NMCL and the James B. Shepherd Trust (JBST), which owns Berkey’s intellectual property. That lawsuit was dismissed for “lack of standing” as the Court determined that neither NMCL nor the JBST had been harmed by the EPA’s issuing of SSUROs to NMCL dealers and suppliers. In November 2023, an appeal was filed in the Fifth Circuit Court of Appeals because in the view of the Plaintiffs, the Court failed in its requirement to accept all well-pleaded facts as true and view them in the light most favorable to the Plaintiff. While the Court of Appeals denied the motion for an immediate injunction, the lawsuit has not been dismissed and is still active in the Court of Appeals.

Berkey International has now filed an additional lawsuit against the EPA, which cannot be dismissed for “lack of standing”, as an SSURO (Stop-Sale order) was issued to Berkey International. While no one can ever predict what a federal court will do, we are hopeful for an injunction from the District Court Judge in Puerto Rico.

Though Judge Mark T. Pittman (TX) initially dismissed the case due to “lack of standing”, he stated, “In finding that standing is lacking in this case, the Court is in no way disparaging, or opining on, Plaintiffs’ claims. Indeed, if true, the claims are quite concerning.” By this statement, it appears Judge Pittman recognized a real dispute warranting judicial attention.

The new lawsuit can be found here:

January 30, 2024 Update on Berkey Court Case vs. EPA

As was previously announced in August 2023, New Millennium Concepts, Ltd., the brand owner of Berkey Water Systems, filed a lawsuit against the EPA for classifying Berkey Water Filters as pesticides and is seeking an injunction to lift the Stop-Sale order (SSURO) placed on Berkey International—which manufactures and supplies Berkey products to NMCL.

  • In November, NMCL’s case is dismissed due to what the court felt was NMCL’s “lack of standing”. New Millennium Concepts then filed an appeal with the Fifth Circuit Court of Appeals because the court failed in its requirement to accept the Plaintiffs’ arguments and evidence.
  • In January, NMCL’s request for immediate temporary injunction to lift the EPA’s Stop-Sale order against Berkey International was denied by Fifth Circuit Court of Appeals. NMCL files a motion (Appellant’s Brief) rebutting the EPA’s arguments and disputing the District Court’s previous decision regarding NMCL’s lack of standing and how the court erred in dismissing the case.

The Bottom Line

  • District Court Judge in original case stated: “In finding that standing is lacking in this case, the Court is in no way disparaging, or opining on, Plaintiffs’ claims. Indeed, if true, the claims are quite concerning.” By this statement it seems the Judge agrees there is a valid case which deserves action by the court to remedy, if Appellants’ standing could be substantiated.
  • While the Court of Appeals has denied our initial appeal for an immediate injunction, the lawsuit was not dismissed and is still an active case being reviewed by the Fifth Circuit Court of Appeals.
  • NMCL is continuing to conduct business as we have been doing, and hope the court will make a speedy decision that will enable us to resume manufacturing Berkey products. Rest assured that NMCL and its legal counsel are considering all other legal remedies to resolve the issue.

For more in depth background of the lawsuit against the EPA please see:

September 12, 2023 Berkey Files Suit against the EPA

August 9, 2023 – New Millennium Concepts, Ltd. (“NMCL”) and the James B. Shepherd Trust, the brand owner of Berkey Water Systems, filed a lawsuit against the EPA (United States Environmental Protection Agency) this week seeking to stop its unjustified treatment and perceived persecution of Berkey Water Filters based on the EPA’s decision this year to treat Berkey Water Filters as though they are pesticides, rather than water filters.

For more than a quarter of a century, Berkey has provided water filters to the public, providing an effective, economical means of removing harmful contaminants from freshwater sources for consumers to have clean water at home or on the go.1 In fact, an entire generation has grown up with a Berkey filter in their kitchen. If the EPA wants to regulate gravity-fed mechanical water filters, it has a process to follow, at the very least. Berkey’s filters have never caused any harm to anyone, and the removal of Berkey filters from the market inexorably means that Berkey owners will not be able to replace the filters in their systems and therefore, the demand will be met with untested knockoff and counterfeit filters that claim to be replacements that provide the same benefits—when in fact they do not.2

The EPA’s decision to persecute the market leader may well cause actual damage to the American people who the EPA is supposed to be protecting. For example, on July 11, 2023, CBS recommended the Travel Berkey system, both in print and in their broadcast news, based upon the Environmental Working Group’s testing that found Travel Berkey systems removed toxic PFAS to below detectable limits3. And on June 7, 2023, popular consumer health advocate Mike Adams recommended Big Berkey systems reporting that they removed an impressive 99.99% of radioactive cesium-137.4 However, EPA Region 8 is actively working to make these systems unavailable to the American people.

Berkey’s filters have never caused any harm to anyone, and the EPA’s arbitrary—and arguably irrational—new interpretation of its regulations would have a huge impact, directly threatening not only the jobs of  500+ employees globally, lost sales for Berkey distributors and retailers around the world (some of which sell only Berkey products—effectively putting them out of business) and also the well-being of the American people, the very consumers who the EPA is supposed to protect. Moreover, it would have the same impact on other outdoor water filter manufacturers, potentially putting them out of business as well.

The EPA has been regulating pesticides since 1947, mostly through the Federal Insecticide, Fungicide, and Rodenticide Act.5 FIFRA is exactly what it looks like – a law that seeks to regulate chemical pesticides, primarily for agricultural purposes. But the law distinguishes between actual pesticides, “substances or mixtures of substances intended for preventing, destroying, repelling, or mitigating any pest”, and “treated devices”, which use registered pesticides in their construction, e.g., seeds that are sold after being treated with a registered pesticide.

The EPA has never sought to force registration of mechanical-type water filters as pesticides until last year, when the EPA decided to start regulating Berkey’s water filters without warning after more than two decades of indisputably safe manufacture and sale.

Though there was no notice or opportunity to discuss that issue, Berkey and its manufacturing arms agreed to a request from the EPA for Berkey filtration products to be identified as “treated devices” (which is a different classification than a pesticide or a pesticide device), because they incorporate silver (a registered pesticide) in their filter media (a common additive in water filters which does not leach into the water) that protects the filter from biological grow through, a common problem with water filters.

Berkey has not hidden from the EPA, and has tried to comply with applicable laws and regulations regarding the manufacture and distribution of Berkey products. First, Berkey products were designated by the EPA as treated devices; the EPA then reinterpreted their rules and arbitrarily reclassified Berkey filters as a pesticide, issuing orders (without due process) preventing Berkey filters from being sold in some parts of the country by select Berkey dealers and vendors that received Stop-Sale Orders. This change in the rules is without notice or a shred of legal support. Berkey’s filters are not “substances or mixtures of substances intended for preventing, destroying, repelling, or mitigating any pest”, as FIFRA defines pesticides. Rather, they mechanically remove contaminants through a tortuous maze of micropores, absorption and ionic adsorption.6

A problem arises when a water filter system is classified as a registered pesticide because a whole host of time consuming regulations and requirements go into play, including onerous labeling requirements that must be placed upon all packaging. Basically, the regulations that require labels to go on the packaging assert that the product is a hazardous material. Other required labels include hazard precautionary statements, environmental hazards statements, directions for use and storage, disposal statements and mandatory statements that ensure the proper use of the pesticide and to prevent the occurrence of unreasonable adverse effects on the environment, which is defined in FIFRA etc. Therefore, Berkey would be required to label its water filters with pesticide language that could be very disconcerting and frightening to its customers—especially when similar and competing products are not being held to the same standard or requirements. Moreover, pesticide registration is an expensive process that can take years to get EPA approval and in the meantime, Berkey products would not be available to the American public.

As an administrative body, the EPA does not make actual law; its authority is limited to creating rules, which enforce laws that are passed by the United States Congress. As it is making rules, it is obligated to give notice of new rules and take input from those who will be impacted, which in our case did not occur.

In part, the EPA is excusing its new regulations that now classify Berkey filters as a pesticide on a notice issued in 2007 regarding electrode-equipped ion-generating devices, asserting that the use of silver in Berkey filters makes the filters into ion-generating devices, even though the 2007 notice specifically excepts that interpretation.

NMCL, and the family-owned trust that owns Berkey’s intellectual property and manufacturing authority, has employed Norred Law to sue in federal court, and seeks an injunction to force the EPA to follow its rule-making process before enforcing new regulations.

The case has been filed in the Northern District of Texas, in cause 4:23-cv-00826, and is before Judge Pittman, who has ordered briefing on the requested injunction before the end of August. Read Mr. Shepherd’s Declaration and the Original Complaint here:

[1] During their history, Black Berkey Elements have undergone what we believe to be the most rigorous testing of any other gravity-fed water filter elements. Berkey systems are simple and easy to use and require no electricity, costly installation, or tools, providing economical, long-lasting water filtration for just pennies a gallon.

[2] Black Berkey Elements are composed of a proprietary blend of multiple media types designed to work synergistically and target specific contaminants that far exceed the reduction capabilities of carbon block filters that are solely composed of activated carbon. See



[5] FIFRA, 7 U.S.C. ch. 6 § 136.

[6] Mechanical filtering refers to a water filter construction where contaminants are caught and removed by a tortuous maze of micropores in the filter, absorption and ionic adsorption.

Berkey Water Purifier vs. Brita Water Filter

Berkey Water Filters vs Brita's: What is the Difference?

We are often asked what's the difference between a Berkey water filter and a countertop Brita water filter. Our first response is usually an ironic "marketing", but of course, the differences run much deeper and a Brita water filter does not compare favourably to the Black Berkey filters on many levels of comparison.

How does a Brita water filter compare to Berkey in terms of heavy metals elimination? A few years ago the Health Ranger published the results of heavy metal removal by various plastic counter-top water filters, the results were not encouraging. The Brita had the following removal percentages: Aluminum -33.9% (Aluminum was actually added to the water by the Brita filter, although this may be an aluminium trioxide which is chemically inert and therefore harmless. We don't know if the Health Ranger lab was able to make this distinction.), Copper 8.6%, Arsenic 12.1%, Strontium 3.6%, Cadmium 6.6%, Cesium 9.5%, Mercury 74.6%, Lead 14.1% and Uranium 10.0%. The Black Berkey filters were found by independent lab tests to remove the heavy metals listed above to a degree of 99% or higher and the radioactive elements listed above to a degree of 95% or higher.


Brita vs. BerkeyBrita filter and Big Berkey


We have not been able to find information regarding pathogenic bacteria removal by the Brita filters as they do not publish any information regarding pathogenic bacteria elimination on their website. This leads one to suspect that bacteriological contamination is either not removed or at such a low level that Brita does not divulge this information. There was a study done years ago in which the bacterial counts were actually found to increase in the Brita filtered water. This is where the Black Berkey filters are in a class of their own and why they are classified as water purifiers as opposed to water filters, the Black Berkey filters remove pathogenic bacteria to a level of 99.9999999%.

The Brita filter cartridges must be replaced every 4 weeks or 100 liters whichever comes first, if the source water is harder than 12 degrees of Clarke hardness then the Brita water filter cartridges must be replaced even sooner. A set of 2 Black Berkey filters can filter up to 22,700 liters. Our replacement calculator allows you to calculate how long your Black Berkey filters will last based upon your own usage.

One might expect the Brita filters to be much cheaper than a Berkey water purifier over a lifespan of 22,700 liters, the opposite appears to be true. At the time of writing (March 2018) the total cost of a Brita water filter is £1130 (€1519), based upon 19 Brita filter packs of 12 filters (£59.50/€79.95 each) and total of 22,700 liters of water to be filtered. The cost of a Big Berkey including 2 Black Berkey filters is £253/€279.

If you need any help in choosing which Berkey water filter system best suits your needs see Choosing a Berkey Water Purification or send us an email at:

Plastic Fiber Pollution and the Berkey Filters

Plastic Fiber Pollution

Plastic fiber pollution of our drinking water has recently come into the news. Whereas earlier concerns were about plastics in the oceans it now appears that micoplastics have entered the food chain on a grand scale. This microplastic contamination has found it's way into drinking water around the globe. A shockingly high 83% of the tap water samples collected from around the world were found to be contaminated with microplastic fibers. We have received many questions about whether the Black Berkey filters are able to remove this plastic fiber pollution.

Plastic Fibers in Tap Water reported by Berkey Water Filters EuropePlastic Fibers in Tap Water

An extensive investigation of plastic fiber pollution in drinking water found that these analyses caught particles of more than 2.5 microns in size,” 2.5 microns is 2.5 micrometers. A micron is an abbreviated term for a micrometer which is a millionth of a meter (1/1,000,000 meters). For size comparison, a human red blood cell is about 5 microns across and a human hair is about 75 microns across. Working down to a smaller scale 2.5 microns would be 2,500 nanometers.

The Black Berkey water filters can reduce viruses down to the nanometer scale, in the tested range of 24-26 nanometers. 24-26 nanometers is .024 to .026 microns…in other words, much smaller than the plastic fiber particles being found in drinking water. The fact that Black Berkey water filters have been tested to remove viruses in the nanometer range suggests that contaminants much larger in size, such as plastic fibers would also be removed. Nonetheless, since actual testing of the Black Berkey filters for plastic fiber elimination has not yet been conducted, Berkey cannot yet officially make that claim. Once independent lab testing has been done we will publish the results as soon as they become available.

Berkey water filter system is the means to protect yourself and your family against the continuing degradation of our commons.

GenX Contaminant Removal & Black Berkey Filter 

What is GenX?

GenX is the trade name for a chemical that was introduced in 2010 as a so-called “safer” replacement for a toxic contaminant known as PFOA (perfluorooctanoic acid, commonly called C8). A "safer" alternative or maybe a less well known and thus less well regulated alternative, who knows? Like its predecessor, GenX enables the production of common household products such as non-stick teflon pans and water-repellent fabrics. Although few health studies are available on GenX, toxicologists say GenX is chemically almost identical to C8, thus sparking concerns about adverse health effects. GenX has recently come in the news in The Netherlands as it has been found that Chemours (formerly DuPont) has been dumping GenX contaminated effluent into the local river as well as the air through it's chimneys. GenX is not currently regulated by EU institutions and is able to circumvent further investigation at the moment due to this gap in regulatory oversight.

GenX report from Berkey Water Filters Europe
Despite the fact that this chemical compound is virtually identical to it's predecessor C8, which is a recognized carcinogen Chemours has the gall to deny that the substance causes cancer and argues the lab results say nothing about the impact on human health. The company is also refusing to say how much GenX it is allowed to emit under its current environmental permits. Dutch regulatory agencies are waffling as well and have not pushed for an outright ban of GenX emissions.

PFOAs are "Organofluorine Compounds" and the Black Berkey filters are very effective at removing these organic contaminants from water, to levels of 99.9% or greater. Further, the Black Berkey filters have been tested for PFC reduction and achieved levels down to two parts per Trillion… extremely small.

Black Berkey Perfluorinated Chemical Removal Report As such, the expectation is that the Black Berkey filters would reduce GenX in water. It is important to note that Berkey does not have actual testing for these particular contaminants, as of yet. Without specific testing we cannot make any claim on this specific chemical, but the data suggest that the Black Berkey filters would likely be very efficient at removing GenX, given that it is a fluoropolymer resin similar to PFOA.

Roundup Glyphosate Update

Monsanto and it's weedkiller Roundup is back in the news, this time not for falsifying glyphosate carcinogenic test results, but due to the poisoning of Dutch drinking water. According to the Dutch water company Vitens 50% of it's customers use Roundup in their gardens not realizing that this herbicide eventually ends up in their drinking water. This is not to mention the widespread and intensive use of Roundup and other herbicides in modern agriculture. The Dutch Institute for Health and Environment (RIVM) found that a quarter of the wells it tested were contaminated by Roundup residues. The RIVM says there is no reason for concern but as we noted in our previous post; based on a study by King's College, London the current acceptable levels for glyphosate in drinking water are way too high. The only acceptable level of glyphosate and other herbicide residues in drinking water is zero.

Boycott Roundup as the glyphoste in the weedkiller is poisoning the Dutch drinking waterBoycott Roundup

We cannot expect any protection from the powers that be. The European commissioner for Health and Food Safety sees no need to ban Roundup as according to him "the science is divided on whether Roundup is carcinogenic". The European Chemicals Agency (ECHA) has recently found glyphosate not to be a human carcinogen which contradicts the findings of the World Health Organization. It's quite apparent to even the casual observer that although the science may seem to be divided what seems to be even more the case is that the regulatory agencies appear to be compromised as evidenced by the California court case we highlighted in our previous Berkey blogpost.

In any case Vitens and other Dutch water companies are setting a good example by suggesting to all their customers to not use Roundup or Imex as a weedkiller in their garden. In the meantime using a Berkey water filter will keep your drinking water pure and prevent you and your family being exposed to a wide range of chemical contaminants.

The Berkey Roundup Roundup

Monsanto, the company that gave us Agent Orange the chemical agent used for exfoliating and permanently poisoning the Vietnamese jungle during the Vietnam war has now been found to have colluded with US regulators in falsifying carcinogenic studies for Roundup, the number one weed killer in the world. The UK mainstream media or more accurately the UK presstitutes are strangely silent on this, not a word from The Guardian, The Daily Torygraph or the BBC to name but a few. The Independent actually has the gall to waffle for Roundup in this article about "the controversial weed killer", controversial only in the eyes of those opposed to science as one perceptive commenter noted.

Roundup Weed Killer reported by Berkey Water Filters Europe

First of all in a study released in January by King's College, London and published in Nature magazine it was found that glyphosate, the active ingredient in Roundup, led to severe liver damage in rats. This at dosages 75,000 times less than what is permitted by European law. No attention was paid to this by any of the British media. A question can then be fairly posed: how much do Monsanto, garden centers, agricultural suppliers, farmer's unions etc. advertise in British media to facilitate no attention being paid to this damning research? Is the sin of omission equal to the sin of commission, or isn't it?

It now appears that Monsanto has never "conducted chronic carcinogenity studies" and that Monsanto cannot claim that "Roundup does not cause cancer", this was said by Monsanto's own leading toxicologist in an email made public in a lawsuit currently being heard in California. A leading official with the US Environmental Protection Agency (EPA) emailed Monsanto saying he could "kill any potentially damaging research" and if he could kill this he "should get a medal". Monsanto's response to these damning revelations is; "It’s not an effort to manipulate the system". If it wasn't so mendacious I would have fallen off my chair from laughter at such a transparently false rebuttal from Monsanto.
Another legitimate question is how do the thousands of people working for Monsanto, a company worth $60 billion, sleep at night and justify this criminal behavior to themselves and their families?

Boycotting Roundup and all Monsanto products is at least something we can do as our regulatory agencies are apparently compromised and corrupted by lobbyists. A lobbyist being a euphemism for one who bribes our government representatives. Fortunately we can also protect ourselves from drinking water poisoned by Roundup's active ingredient glyphosate by using the Berkey water filter systems. The Black Berkey water filters, the water filters against which all other gravity fed water filters are compared protect your family's health with clean drinking water.

Drinking Water Quality in the UK

We are all dependent upon a safe and reliable supply of high quality drinking water. In general the water companies in the UK meet this need, maintaining the network and regularly testing for contamination. Nonetheless accidents do happen due to mistakes, delayed maintenance, negligence etc. and your water supply can then become compromised. Not all drinking water accidents reach the news but in the past few years there have been incidents in Greater ManchesterSouth Yorkshire and Derbyshire to name a few. These incidents will most likely increase in the coming years as maintenance is delayed or postponed and necessary investments are sacrificed for so-called “shareholder value” . Due to privatisation the water companies are now largely driven by profit motive which is in direct conflict with their primary obligation the delivery of clean drinking water at an affordable price for all. The combined CEO salaries of the 19 private water monopolies is 10 million pounds and your water bill has risen by 40% since privatisation. You don’t need to be a weatherman to see which way the wind blows to quote His Bobness. These CEOs and the private equity firms who own the water monopolies do not have your best interests at heart.

River Itchen near Ovington.River Itchen near Ovington.

Berkey water filter system can at the least give you and your family the assurance that when things do go wrong with the water supply you have a safe source of water at hand. Of course one needn’t wait until an emergency a Berkey water filter system is your guarantee of clean, pure water daily for only pennies on the gallon.

Black Berkey Filters Lead Removal Lab Test Results

Berkey Water Filters Europe have just released the latest round of independent lab testing done on the Black Berkey filters for the removal of lead from drinking water. As expected the Black Berkey filters performed very well and achieved a more than 99% level of lead removal.

The use of lead in water pipes and plumbing has been prohibited in the UK and the EU since the 1970s. If the kitchen has been modernised since the 1970s then the presence of lead piping is also highly unlikely. In pre-1970 buildings it is possible that the service pipe connecting the property to the mains as well as the interior plumbing may be made of lead or contain lead solder. In hard water areas this issue is partly mitigated by the build up of limescale on the pipes, in soft water areas there is a higher probability of lead entering the water supply.

If you suspect that there is lead piping in your house the easiest way to check is whether there are lead pipes leading to your kitchen tap. Lead piping is soft, looks dull grey and can be scraped with a coin to show the shiny surface underneath. Most water companies in the UK offer free water testing for the presence of lead and they can also tell you if there is a history of lead pipe removal in your area.

Lead atomic symbolLead atomic symbol

Black Berkey Lead Removal

In the event of lead piping or solder in your house the obvious thing to do is to have it removed as soon as possible. If for whatever reason this is not possible in the short term then the next best line of defence against lead in your water is of course a Berkey water filter system. Berkey water filters do not only remove lead but a wide range of contaminants unfortunately commonly found in our drinking water such as pharmaceuticals, glyphosate, chloramines etc. For a complete overview of the independent lab testing commissioned by the Berkey manufacturer see: Berkey Lab Tests.

Drinking Water Issues for October

Ireland a step closer to banning fracking
Awareness of the dangers that fracking poses to fresh water is apparently rising as the Irish parliament has passed a bill proposing to ban fracking in Ireland. All legal and parliamentary hurdles have not been cleared and the fracking industry shills will most likely be lobbying (a polite euphemism for bribing) in the background to overcome this setback. Let's hope the Irish government has more integrity and grit than the UK government as regards fracking.

Support for Fracking Falls to Lowest Levels

Fracking support falls off cliff
According to the government's own pollsters support for fracking has fallen to it's lowest level yet. Nonetheless the government's policies remain blissfully unchanged. This article is a piece of fluff in which the Guardian attempts to preserve so-called journalistic objectivity in the name of fairness. Whatever happened to journalistic integrity? Clean drinking water is a basic necessity of life and every attempt to undermine the quality of our common drinking water for private gain should be pilloried and exposed by the press. Apparently the Guardian didn't get the memo.

Support for fracking in the UK at lowest levels since surveys began
Support for fracking in the UK at lowest levels since surveys began.

For those concerned about their water quality and safety the Berkey systems provide a reliable and inexpensive source of water for pennies on the gallon. According to an estimated 30% to 70% of the fluid used in fracking will resurface: polluting surface water, ground water and reservoirs. Some of the toxic contaminants found in fracking waste water are radium-226, strontium, benzene, toluene, xylene and ethylbenzene among others. All of these toxic contaminants are removed by the Black Berkey filters, this has been confirmed through the years by various rounds of  independent lab testing.

The powerful Black Berkey water filters also remove or reduce viruses, pathogenic cysts, parasites, pharmaceuticals, harmful chemicals such as herbicides and pesticides, VOCs, detergents, organic solvents, cloudiness, trihalomethanes, silt, sediment, heavy metals, foul tastes and odors, yet they are able to leave undisturbed the healthful and beneficial minerals that your body requires.

Beta Radiological Removal Tests

The Berkey manufacturer, NMCL, has recently released the second round of independent lab testing for the removal of radioactive isotopes. This round for the testing of beta radiological contaminants was done for the following radioactive isotopes:

Californium-251 and -252
Iodine-129 and -131

The Black Berkey filters were found to remove the radioactive contaminants listed above to a level of 95.3%.
The complete radiological test results can be found here: Radiation Test results.