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BIOHAZARDS! | The under-estimated problem of biological hazards at work
From natural fibres to furry critters, creepy crawlies to coronavirus, biological hazards in the workplace are a major and seriously under-estimated problem. Hazards editor Rory O’Neill says unions need to be vigilant for the infections, lung diseases, cancers and other related conditions that see half a million workers worldwide die each year.


Global estimates on biological risks at work, based on International Labour Organisation (ILO) data and published online in the journal Safety and Health at Work on 5 October 2023, identify a major problem that has remained under the occupational health radar.

Exposure to biological hazards at work accounted for over 550,000 deaths in 2021, the most recently reliable figures show, considerably higher than the annual toll from work-related fatalities. The new estimates indicate there has been an increase in disability adjusted life years (DALYs) attributable to biological exposures at work.

Related conditions included infectious diseases, restrictive and obstructive lung diseases, cancers, poisonings and injuries. Classic occupational diseases include cotton lung (byssinosis), farmers' lung (fibrosing alveolitis) and bakers' asthma.

Several occupational conditions, including cancers and lung diseases caused by biological exposures at work, are named explicitly in ILO's List of Occupational Diseases (Recommendation 194). Hundreds of additional exposures to irritants, sensitisers, carcinogens and other hazards fall within the list's qualifying terms for recognition as occupational diseases, causing conditions from asthma and cancer to anaphylaxis.

What’s the problem?

The ILO Technical Guidelines on biological hazards in the working environment agreed in 2022 and published in July 2023 established a broad definition of biological hazards at work. As well as the full spectrum of biological agents “and their associated allergens and toxins”, the guidelines specify the problem extends to “infectious and non-infectious diseases and injuries” and biological hazards from “vectors or transmitters of disease.”

INFECTIOUS PROBLEM? It’s more than infections that can bug us at work. Dusts, insects, rodents, reptiles and plants are among an extensive range of hazards that mean whatever your job, you may be exposed to biological hazards at work that can lead to diseases, disasters, outbreaks and injuries. More

Global unions had since 1993 called for an ILO Convention on biological hazards at work, but it was only in March 2021 that ILO’s governing body (GB) agreed a new standard on occupational health and safety protection against biological hazards would be negotiated at the ILO’s International Labour Conferences in 2024 and 2025.

The International Trade Union Confederation (ITUC), which will coordinate the union team in these negotiations, contends the new convention must reflect the broad scope established in the technical guidelines, and in addition to infectious and non-infectious diseases believes this standard must include poisonings, cancers and injuries – puncture wounds, cuts, abrasions, irritation and other harms related to the physical properties of biological agents and substances.

It should also cover explosions, asphyxiations or other physical risks related to the presence of the whole range of biological hazards in the work environment, and other conditions (sequela) arising out of exposures, including cardiovascular and psychosocial conditions.

Organic dusts like sugar and flour are an explosion risk; stored products can release gases or displace oxygen. And infections and occupational diseases can leave permanent reminders, like post viral fatigue, Long Covid or damage to heart valves.
Risks are present in all sectors, from infections and allergies in health, social care and service sectors workers, to infections, poisonings and other harms resulting from exposure to plants and vectors in construction, agriculture and waste, to emerging health issues in the biotech industry.

Vigilance is key. There is inevitably another ‘novel’ threat lurking. Covid-19 is a relative newbie, but it followed on from other workplace novel coronavirus outbreaks in the last two decades. SARS and MERS were far less transmissible but more deadly to those infected.

A systematised review of studies on biological hazards at work and their effects, published in the journal Safety and Health at Work on 5 October 2023, noted: “Biological hazards, both infectious and non-infectious, constitute significant threats to health in numerous industrial sectors and workplaces around the world, often leading to occupational and work-related diseases,” with relevant hazards including “infectious and non-infectious agents, endotoxins, bioaerosols, organic dust, and emerging agents.”

TOXIC TOBACCO  Workers handling tobacco leaves can develop severe nicotine poisoning. Green Tobacco Sickness sees workers suffering nausea and vomiting that can lead to hospitalisation. Affected workers are also at greater risk for heat-related illness – a potentially deadly condition. Hundreds of other plants can pose a risk to agriculture, horticulture and outdoor workers, including poison ivy, poison oak, poison sumac, giant hogweed, ragweed, foxglove and oleander.

The review added the risks are “very significant in many occupational activities, involving different modes of exposure and different health outcomes,” with further studies necessary “to combat all hazards to human health, including emerging ones.”

The growing public health threat from antimicrobial resistance (AMR) raises concerns that known risks can lead to new and more serious outcomes at work. This, and lessons learned from a succession of ‘novel’ coronavirus outbreaks impacting on workplaces – in sequence SARS, MERS and Covid-19 – demonstrate the need for vigilance, effective surveillance and a preventive, precautionary approach to risks, all factors that should be reflected in a new ILO standard.

Protect yourself

The Covid-19 pandemic demonstrated that to secure an effective public health response, with many health, food, transport, education and other workers deemed ‘essential’ so not able to stop work or work from home, occupational health and safety rights had to be supplemented by wider employee protections and support.

Income support and better, more comprehensive access to sick pay, available to all workers, was determined to be critical to limiting workplace infections and related transmission to the wider population. Low paid workers, particularly, need financial security to make sick leave an affordable option.

COTTON PICKING BAD  Cotton dust can cause the potentially fatal lung disease byssinosis, occupational asthma and respiratory irritation.

Measures to prevent the cross over of animal diseases to humans – for example, recent interventions to prevent Avian Flu in poultry or mink farms, or BSE and TB in cattle – can involve culls and the temporary or permanent closure of businesses on public health grounds. Income support and employment protection measures are necessary to achieve effective implementation of related public health interventions.

Where the law falls short, your best protection is the union. Collective bargaining saves lives – official.

Mortality from Covid-19 in the US: Did unions save lives?, published by the ILO in November 2023, found union-negotiated safety measures during the pandemic led to reduced infection rates. It found a 10 per cent increase in unionisation was associated with an equivalent reduction in Covid-19 mortality, from 26 deaths per 100,000 workers to 24 per 100,000 workers.

US studies established union action reduced community Covid-19 infection rates through securing better reporting and better protective/preventive measures. Studies in nursing homes showed lower rates of both Covid-19 patient deaths and worker infections in unionised workplaces.

Key references

ITUC briefings




Danger! Biological hazards at work

Conditions related to microorganisms

Covid-19 highlighted the pandemic level risks that can arise from exposures at work, with many workers in health and social care, transport, food, education, prison and other sectors in the exposure frontline. The global estimate based on ILO data put this toll from Covid-19 in 2021 alone at over 223,000 deaths.

Biological agents can include:

Viral conditions like SARS and Middle East Respiratory Syndrome (both, like Covid-19, caused by coronaviruses), Avian influenza virus (Bird flu), Swine flu, Zika virus, Ebola and West Nile virus;
Tick-borne diseases like Monkey fever and Lyme disease;
Bacterial conditions like MRSA, Anthrax, Brucellosis, Leptospirosis (Weil’s disease), Psittacosis, Legionnaire’s disease, Tuberculosis (TB), and Q-fever;
Blood borne diseases like HIV and Hepatitis B and C.
Mould or fungal spore related conditions like Histoplasmosis and Extrinsic Allergic Alveolitis (eg. Farmer’s lung).
Prion-related conditions (Spongiform encephalopathies) – eg. Bovine Spongiform Encephalopathy (BSE).

Non-infectious risks

Many of the classic occupational diseases associated with 'biological hazards' or 'biological agents' are not infections – for example byssinosis, a lung disease caused by cotton dust exposure which has been recognised for hundreds of years. It is critical any new instrument addresses all the risks posed by biological hazards at work.

Irritant and allergic reactions  Hundreds of biological substances are associated with work-related allergies, including cereals, tea, coffee and bean dust and shellfish. Many plants encountered at work, including hogweed, poison oak and poison ivy, cause severe reactions. Occupational asthma, rhinitis and dermatitis are among associated conditions. Asthma caused by ‘recognised sensitising agents or irritants inherent to the work process’ is included in the ILO list of Occupational Diseases (Recommendation 194). Diseases related to latex (natural rubber) exposure are also included on the ILO list, with associated health effects including allergies and potentially fatal anaphylaxis.

Organic dust related diseases  The ILO List of Occupational Diseases include lung diseases caused by cotton (byssinosis), flax, hemp, sisal and sugar cane (bagassosis). Extrinsic allergic alveolitis caused by the workplace inhalation of organic dusts (for example farmers’ lung) or microbially contaminated aerosols (in metalworking fluids or emanating from air-conditioning systems, for example) is also on the list. Organic dust toxic syndrome – chills, malaise, myalgia, a dry cough, dyspnea, headache and nausea occurring after heavy organic dust exposure – is an established work-related condition.

Occupational cancers  A number of cancers are associated with exposure to biological hazards at work. Wood dust exposure is related to nasal cancers and has been linked in studies to lung cancer; wood dust and cancer is recognised explicitly on the ILO’s list. Like wood dust, leather dust exposure is recognised by the UN’s International Agency for Research on Cancer (IARC) as a cause of nasal cancer. Working with natural rubber and leather is associated with bladder cancer. Exposure to aflatoxins, found in livestock feed, nuts and other food products, is recognised by IARC as a cause of liver and bile duct cancers in humans. Cancers associated with occupational infection with Hepatitis B virus (HVB) or Hepatitis C (HVC) are included in the ILO occupational diseases list. The new global estimates based on ILO data identify several other jobs involving exposure to biological substances that have been linked to cancers.

Poisonings  Many biological substances can be a toxic hazard at work, for example tobacco workers suffer from Green Tobacco Sickness and many commonly encountered plants can be a serious hazard to outdoor or horticulture workers. Contact with poisonous insects, spiders, venomous snakes and other animals may be a considerable risk in agricultural, construction and other sectors, particularly for outdoor workers.

Physical hazards  The physical properties of some biological substances encountered at work can lead to workers’ being harmed. Interdigital pilonidal sinus of the hand is an occupational disease of barbers or hairdressers, where fragments of hair become embedded in the skin – barbers refer to them as ‘hair splinters’ – sometimes leading to cyst formation. Similar problems can occur from wood splinters. Cotton pickers can suffer puncture wounds and cuts from handling the cotton boll and leaves. Cotton lint is highly flammable. Fine organic dusts are a notorious explosion risk, and explosions and associated fires in flour, sugar, spice, other food processing and woodworking facilities are frequently deadly. The new global estimates suggest over 20,000 workers each year may die as a result of injuries sustained while handling animals at work.

Biotech industry  The rapid growth of the biotechnology industry has seen workers exposed to risks in new settings. Workers in biogas facilities face exposure to microorganisms and asphyxiation and explosion risk from gases generated in the process. The manufacture of biological detergents can use agents like amylase, derived from bacteria including B subtilis, and which have been linked to occupational asthma. And fungi, which can cause conditions like aspergillosis, are increasingly used in novel applications, for example as plastic or meat substitutes.

Secondary health effects  As Hepatitis-related cancers demonstrate, there can be dangerous sequelae to the original health condition caused by exposure to a biological hazard at work. Almost one in ten workers with a Q fever infection as a result of handling fleeces or hides, for example, may develop Q fever endocarditis, a potentially fatal heart condition. Post-infection fatigue and other health impacts – for example Long Covid – are well reported. Psychosocial disorders, including post-traumatic stress, anxiety or depression, are established consequences of work-related ill-health.

These lists are not comprehensive, but indicative of the broad range of jobs and working environments where biological substances can present an occupational risk.


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From natural fibres to furry critters, creepy crawlies to coronavirus, biological hazards in the workplace are a major and seriously under-estimated problem. Hazards editor Rory O’Neill says unions need to be vigilant for the infections, lung diseases, cancers and other related conditions that see half a million workers worldwide die each year.

What’s the problem?
Protect yourself
Key references
ITUC briefings

Danger! Biological Hazards at work
Conditions related to microorganisms
Non-infectious risks

Hazards webpages
Deadly business

ITUC briefings
Biological hazards and the work environment: Trade union position and priorities ahead of the International Labour Conference 2024 first discussion on occupational safety and health protection against biological hazards, ITUC, December 2023.

Peligros biológicos y entorno laboral: Postura y prioridades de los sindicatos de cara al primer debate de la Conferencia Internacional del Trabajo 2024 sobre protección de la salud y la seguridad en el trabajo contra los peligros biológicos, CSI, Diciembre 2023.

Risques biologiques et environnements professionnels: Position et priorités des syndicats en prévision de la première discussion de la Conférence internationale du Travail 2024 sur la protection de la sécurité et de la santé contre les risques biologiques sur les lieux de travail, CSI, Decembre 2023.