Published: 26 February 2026
By EMFSA

Class 2B Possible Human Carcinogens

Class 2B Possible Human Carcinogens are substances or exposures identified by the International Agency for Research on Cancer (IARC) as possibly carcinogenic to humans. This classification is based on limited or inconclusive evidence in humans, supported by preclinical studies in animals or mechanistic research. Importantly, being classified as possibly carcinogenic indicates hazard, not proven risk at typical environmental exposure levels.

Evidence and Examples of Class 2B Agents

To illustrate the diversity of evidence, consider two notable examples. In November 2025, IARC classified vinclozolin, a pesticide, as “possibly carcinogenic to humans,” based on animal studies showing liver and reproductive effects, including multigenerational impacts. Human data remain limited, but the experimental findings were sufficient to support a Group 2B designation.

Radiofrequency (RF) electromagnetic fields were classified earlier, in 2011, based primarily on limited human epidemiological evidence suggesting a potential association with certain brain tumors, alongside mechanistic data from preclinical studies available at that time. Following this classification, additional research, such as the NTP 2018 animal study, investigated high-dose RF-EMF exposure in both rats and mice and observed small increases in certain tumors in male rats, particularly cardiac schwannomas and some brain gliomas. Although these post-classification studies contribute to ongoing research, they did not influence the original Group 2B designation. Evaluations by the WHO EMF Project and IARC continue to assess new evidence to determine whether future reclassification may be warranted.

At the same time, international review efforts have continued. The WHO EMF Project and IARC are assessing newer evidence to determine whether the existing classification remains appropriate or whether future reassessment may be warranted.

Taken together, these examples show that Class 2B agents represent signals of potential carcinogenicity that warrant further research, regulatory attention, and precautionary measures, while reinforcing that current evidence in humans remains limited or inconclusive.

Regulatory and Precautionary Approaches

Regulatory responses vary depending on the type of agent and the strength of evidence available. In some jurisdictions, vinclozolin has been restricted or phased out following toxicological concerns. By contrast, regulators manage RF-EMF exposure primarily through guidelines and public health recommendations.

It is important to clarify that the World Health Organization does not set exposure limits directly. Instead, independent scientific bodies such as ICNIRP and IEEE develop exposure guidelines, while WHO evaluates the broader health evidence and provides risk assessments to governments.

Understanding Class 2B Possible Human Carcinogens

Overall, Class 2B Possible Human Carcinogens indicate that credible scientific signals exist, yet the evidence is not strong enough to establish causation in humans. As a result, the designation encourages further research, careful monitoring, and proportionate precaution, without implying confirmed human cancer risk.

IARC Classification System

The International Agency for Research on Cancer classification system is defined as follows:

• Group 1 — Carcinogenic to humans
• Group 2A — Probably carcinogenic to humans
• Group 2B — Possibly carcinogenic to humans
• Group 3 — Not classifiable as to carcinogenicity in humans

More on the topic: : IARC Monographs evaluation of the carcinogenicity of night shift work https://www.emfsa.co.za/research-and-studies/iarc-monographs-evaluation-of-the-carcinogenicity-of-night-shift-work/

References:

1. International Agency for Research on Cancer (IARC). List of Classifications, including Radiofrequency Electromagnetic Fields. Last updated 25 February 2026.https://monographs.iarc.who.int/list-of-classifications
2. US Right to Know. One Exposure, Twenty Generations Later: The Damage is Unfolding. 2025. https://usrtk.org/healthwire/one-exposure-twenty-generations-later-the-damage-is-unfolding/
3. World Health Organization. International EMF Project https://www.who.int/initiatives/the-international-emf-project
4. WHO Radiation and health https://www.who.int/teams/environment-climate-change-and-health/radiation-and-health/non-ionizing/wireless
5. ICNIRP. Guidelines for limiting exposure to electromagnetic fields (100 kHz – 300 GHz). 2020. https://www.icnirp.org/en/publications/article/rf-guidelines-2020.html

* Image adapted from Photo by Milad Fakurian on Unsplash

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Link to our April 2024 Newsletter

https://mailchi.mp/emfsa/screens-cancer-breast-prostate-iarc-5g

The post EMFSA April 2024 Newsletter appeared first on EMFSA.

Surprisingly little is known about the long-term health effects of tattooing, which has become a global trend in recent decades. Tattoos are often considered an artistic form of self-expression, but from a scientific perspective, tattooing can be defined as the intradermal injection of poorly soluble inorganic and/or organic colour pigments diluted in a carrier liquid. Despite attempts to control the ingredients used in the manufacture of inks at the national and international level, the resulting chemical mixtures often have hazardous toxicological profiles and may contain substances classified by the IARC Monographs programme as carcinogenic (Group 1), probably carcinogenic (Group 2A), or possibly carcinogenic (Group 2B) to humans upon dermal and respiratory exposure. Because most of the pigment particles, which are often nanoparticle-sized, will eventually be transported from the dermis to adjacent draining lymph nodes, exposure to tattoo ink may be systemic rather than locally confined. Therefore, potential systemic health effects of tattoos are not limited to the dermis but could include various types of lymphoma, as well as cancers of the kidney, bladder, and liver.

This website presents the latest research stream from the Environment and Lifestyle Epidemiology Branch at IARC on the potential long-term health effects of tattooing.

https://tattoo.iarc.who.int/

The post Research on Potential Long-Term Health Effects of Tattooing appeared first on EMFSA.

In this month’s newsletter:

➼The ITU World Radiocommunication Conference 2023 (WRC-23) and 6G

➼China

➼BioEM 2023

➼Light Pollution

➼5G & satellites

➼Auditory; tinnitus

➼Experts’ Opinions in Radiation and Health: Emerging Issues in the Field

➼Fauna & Flora

➼Adaptive antennas

➼IARC/WHO & ANSES

➼Commercial surveillance

Read more at:

https://mailchi.mp/emfsa/2023-5g-6g-alan-auditory-tinnitus-who-iarc

The post EMFSA December 2022 Newsletter appeared first on EMFSA.

The intentions are good: help save the planet by reducing energy consumption from streetlights. Claims also include the reduction of light pollution.

However, there could be unintended consequences associated with energy saving LED streetlights.

Artificial Light at Night (ALAN), Light Pollution and Circadian Disruption:

In many cases these new LED streetlights are contributing to light pollution, with serious environmental consequences for humans, wildlife, and our climate.

Since 2017 there is general scientific consensus that light has the most significant outcome on altering any biochemistry in life, either positively or negatively.

So-called “white” LEDs emit a portion of their light at wavelengths below 500 nm (blue). These wavelengths are not beneficial to human and environmental health.

The 2022 National WHO EMF Project Report IAC-ZA  mandates that streetlights are modified/adjusted by changing from an energy flux model (white) to a photon flux model (orange/red). UV is included too and flicker. A photon flux model results in significantly lower energy inputs and is much more beneficial to human health.

Mounting evidence indicates that disruption of circadian regulation is associated with a wide variety of adverse health consequences, including increased risk for premature death, cancer, metabolic syndrome, cardiovascular dysfunction, immune dysregulation, reproductive problems, mood disorders, and learning deficits. Of particular interest here is obesity and breast cancer.

•In 2019 a working group from the International Agency for Research on Cancer (IARC) concluded that “shift work that involves circadian disruption is probably carcinogenic to humans” (Group 2A): IARC Monographs Vol 124 group. Carcinogenicity of night shift work: Lancet Oncology; Published 4 July 2019. DOI: https://doi.org/10.1016/S1470-2045(19)30455-3

•2 June 2020 IARC Monographs Volume 124: Night Shift Work https://tinyurl.com/5tk2y76v

 •In 2016, the American Medical Association responded to the growing body of evidence suggesting that intense LEDs are harmful to human health by recommending that communities change streetlights to “minimize and control blue-rich environmental lighting.”

Energy Flux versus Photon Flux model

Video

25:39 Night Sky, Satellites

26:19 Energy Flux versus Photon Flux model

Western Cape Nature residential estate:

Prone to wildfires, drought and high winds on the coast dune line.

Intervention: external building lighting changed to a Photon-flux model.

Outcome:

•Night sky constellations and satellites were significantly more visible.

•Significant increase in wildlife visibility and engagement within the area. 

•Residents went to sleep earlier and there was a decrease of reported health complaints.

•Decrease in property break in attempts at night. 

•Neighboring vegetation growth on the dune increased, and grass lawn resilience to the summer elements, heat and winds significantly increased as illustrated in the images below.

A Human Right:

On the 28th of July 2022 the UN General Assembly adopted a landmark resolution recognizing the right to a clean, healthy and sustainable environment as a human right and calling for greater global efforts to ensure that principle is upheld. 

This resolution updates the Equality Act under the heading of International Binding Treaties, as per the 2022 National WHO EMF Project Report IAC-ZA

This is not progress!

A LED energy saving street light is placed in very close proximity to a residence (without any warning or consultation with the homeowner). 

The light is so bright that it is impossible to spend time outside at night in the garden.

To make matters worse, the light is on all day.

Imagine the frustration- attempts to resolve the matter are ignored;  enquiries to the municipality in regards to the specifications of the light are ignored or sent from pillar to post.

The public is aware that some smart cities incorporate sensors for air quality, pedestrian traffic, monitoring electricity use and more. In addition some streetlights are equipped for telecommunication purposes. Is it a wonder then that conspiracy theories flourish – when there is such a lack of transparency and cooperation?

“Done well, LEDs could save the planet, in the sense of reining in light pollution,” says astronomer John Barentine, also of International Dark-Sky Association. “Done carelessly, it could be devastating.”

References:

2022 National WHO EMF Project Report IAC-ZA

American Medical Association warns of health and safety problems from ‘white’ LED streetlights https://tinyurl.com/bdcs76cz

UN General Assembly Resolution https://tinyurl.com/y9ksmcyz

Thomas Münzel, Omar Hahad, Andreas Daiber, The dark side of nocturnal light pollution. Outdoor light at night increases risk of coronary heart disease, European Heart Journal, Volume 42, Issue 8, 21 February 2021, Pages 831–834, https://doi.org/10.1093/eurheartj/ehaa866

Miao Cao, Ting Xu, Daqiang Yin, Understanding light pollution: Recent advances on its health threats and regulations, Journal of Environmental Sciences, Volume 127, 2023, Pages 589-602, 1001-0742, https://doi.org/10.1016/j.jes.2022.06.020

Bright LEDs could spell the end of dark skies MIT Technology Review https://www.technologyreview.com/2022/08/17/1057652/outdoor-led-lighting/

Our nights are getting brighter and Earth is paying the price https://www.nationalgeographic.com/science/article/nights-are-getting-brighter-earth-paying-the-price-light-pollution-dark-skies

Shanghai wants to dim light pollution https://www.chinadaily.com.cn/a/202208/05/WS62ec779ea310fd2b29e70776.html

The post Energy Saving LED Street Lights-The Unintended Consequences appeared first on EMFSA.

Bio James C. Lin

James C. Lin is a professor of bioengineering and electrical engineering at the University of Illinois Chicago. At the University of Illinois, Lin has served as head of the Bioengineering Department, Director of the Robotics and Automation Laboratory, and Director of Special Projects in the College of Engineering. He also held an appointment as the NSC Research Chair from 1993-1997. Lin is the author of more than 140 journal papers, and author or editor of seven books. After beginning his higher education at Whitworth College in Spokane, Wash., he received the BS, MS and PhD (1971)degrees in electrical engineering from the University of Washington, Seattle. Lin’s academic career took him from teaching and research in Seattle, on to positions at Wayne State University in Detroit and finally at the University of Illinois-Chicago, where he has served as a professor of electrical engineering, bioengineering and physiology and biophysics since 1980. Professor Lin’s research interests include: Biomedical instrumentation; Electromagnetic Engineering for Biology and Medicine; Imaging and Sensing; Bioelectromagnetics; Mobile Telecommunication Safety; Biological Interactions of Electromagnetic Radiation Including RF (Radio Frequency), Microwaves, and Lasers.

Source:

Proceedings of the Workshop on Conducting Evaluations of Evidence that are Transparent, Timely and Lead to Health-Protective Actions February 8-11, 2021

https://prhe.ucsf.edu/sites/g/files/tkssra341/f/wysiwyg/Proceedings_Final_05_10.pdf

The post Professor James C. Lin – Some Key Differences in the ICNIRP and IARC Evaluations of RF Evidence appeared first on EMFSA.

Note by EMFSA: the doi link above might not be active yet.

Published Ahead of Print / Just Accepted

Abstract

Some historical aspects on late lessons from early warnings on cancer risks with lost time for prevention are discussed. One current example is the cancer-causing effect from radiofrequency (RF) radiation. Studies since decades have shown increased human cancer risk. The fifth generation, 5G, for wireless communication is about to be implemented world-wide despite no comprehensive investigations of potential risks to human health and the environment. This has created debate on this technology among concerned people in many countries. In an appeal to EU in September 2017, currently endorsed by more than 400 scientists and medical doctors, a moratorium on the 5G deployment was required until proper scientific evaluation of negative consequences has been made (www.5Gappeal.eu). That request has not been taken seriously by EU. Lack of proper unbiased risk evaluation of the 5G technology makes adverse effects impossible to be foreseen. This disregard is exemplified by the recent report from the International Commission on non-ionizing radiation protection (ICNIRP) whereby only thermal (heating) effects from RF radiation are acknowledged despite a large number of reported non-thermal effects. Thus, no health effects are acknowledged by ICNIRP for non-thermal RF electromagnetic fields in the range of 100 kHz–300 GHz. Based on results in three case-control studies on use of wireless phones we present preventable fraction for brain tumors. Numbers of brain tumors of not defined type were found to increase in Sweden, especially in the age group 20–39 years in both genders, based on the Swedish Inpatient Register. This may be caused by the high prevalence of wireless phone use among children and in adolescence taking a reasonable latency period and the higher vulnerability to RF radiation among young persons.

Excerpt:

In fact, RF-EMF may now be classified as a human carcinogen, Group 1 [82], [, 83]. However, such classification can only be made by IARC.

In contrast to ICNIRP, some other expert panels such as European Academy of Environmental Medicine [91], the Bioinitiative group [92], and the Russian Commission for Protection from Non-Ionizing Radiation [93], take into account non-thermal RF effects and suggest much lower guidelines for RF exposure.

This review gives insight into missed opportunities for cancer prevention exemplified by asbestos, tobacco, certain pesticides and now RF radiation. No doubt economic considerations are favored instead of cancer prevention. The cancer victim is the loser in terms of suffering, life quality and shorter life expectancy. Also the life for the next-of-kin is affected. A strategy to sow doubt on cancer risks was established decades ago and is now adopted and implemented in more sophisticated way by the telecom industry regarding RF-EMF risks to human beings and the environment. Industry has the economic power, access to politicians and media whereas concerned people are unheard.

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Essay

Abstract

New fifth generation (5G) telecommunications systems, now being rolled out globally, have become the subject of a fierce controversy. Some health protection agencies and their scientific advisory committees have concluded that there is no conclusive scientific evidence of harm. Several recent reviews by independent scientists, however, suggest that there is significant uncertainty on this question, with rapidly emerging evidence of potentially harmful biological effects from radio frequency electromagnetic field (RF-EMF) exposures, at the levels 5G roll-out will entail. This essay identifies four relevant sources of scientific uncertainty and concern: (1) lack of clarity about precisely what technology is included in 5G; (2) a rapidly accumulating body of laboratory studies documenting disruptive in vitro and in vivo effects of RF-EMFs—but one with many gaps in it; (3) an almost total lack (as yet) of high-quality epidemiological studies of adverse human health effects from 5G EMF exposure specifically, but rapidly emerging epidemiological evidence of such effects from past generations of RF-EMF exposure; (4) persistent allegations that some national telecommunications regulatory authorities do not base their RF-EMF safety policies on the latest science, related to unmanaged conflicts of interest. The author, an experienced epidemiologist, concludes that one cannot dismiss the growing health concerns about RF-EMFs, especially in an era when higher population levels of exposure are occurring widely, due to the spatially dense transmitters which 5G systems require. Based on the precautionary principle, the author echoes the calls of others for a moratorium on the further roll-out of 5G systems globally, pending more conclusive research on their safety.

View Full Text

http://dx.doi.org/10.1136/jech-2019-213595

Added by EMFSA, professor John William Frank-background and qualifications:

https://www.research.ed.ac.uk/portal/en/persons/john-frank(9995d84a-0b8f-4273-b942-2478150e3eb0).html

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Martin Röösli https://betweenrockandhardplace.wordpress.com/2020/05/20/martin-roosli-of-icnirp-brief-comments-on-ehs/

Röösli and de Vocht https://betweenrockandhardplace.wordpress.com/2020/05/19/discussion-emf-sensitivity-with-roosli-and-de-vocht/

Denis L.Henshaw reponds to Martin Röösli https://betweenrockandhardplace.wordpress.com/2020/05/21/ehs-debate-on-brhp-denis-henshaw-responds-to-martin-roosli/

Steve Weller of ORSAA, Australia, has provided two long and insightful comments concerning to-date and the further perspectives for research on EHS. https://betweenrockandhardplace.wordpress.com/2020/05/21/ehs-debate-on-brhp-steve-weller-commentaries-on-sensitivity-research/?fbclid=IwAR1vImQflHnNaxWlfKWf_LbZLxWg_NPDEpvTRkJLizzcik-ztVEW_9kvTF0

Graham Lamburn, Technical Manager at Powerwatch UK, provided an interesting comment on the usefulness and validity of data obtained in psychology provocation studies. https://betweenrockandhardplace.wordpress.com/2020/05/21/ehs-discussion-on-brhp-graham-lamburn-on-provocation-studies/?fbclid=IwAR0E-Ewh2tD_JyG-eBZj6jnyy1orzi-XyzsNj9owTJz4uvJh350UyTri48Q

Notes added by EMFSA:

Martin Röösli is Professor of Environmental Epidemiology at the Swiss Tropical and Public Health Institute (Swiss TPH). Röösli is a member in various national and international commissions on environmental health research including BERENIS, advisory group of COSMOS and the Scientific Council of the IARC. He has published numerous scientific papers, reviews and book chapters. Dr Röösli started to serve the ICNIRP Commission in 2016. https://www.icnirp.org/en/about-icnirp/commission/details/member-roosli.html

Frank de Vocht is a Reader in Epidemiology and Public Health, and joined the Centre for Public Health, which is part of Population Health Sciences at Bristol Medical School in 2014. blog: http://www.funpolice.eu/

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The measure applies the precautionary principle pending further scientific investigations on the impact of the new technology on public health.

Source PICCHIO NEWS 

Read more at the link:

https://picchionews.it/attualita/potenza-picena-il-sindaco-tartabini-vieta-la-sperimentazione-o-installazione-del-5g?fbclid=IwAR2_RcADwNnQjrLsFRP9gcb08QDNfBP-UduxaW1pJ85deNF2CyWj7r5T-P4

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