Asthma affects 1 in 12 adults in the UK, with research suggesting that work-related factors could account for up to 15% of cases of asthma in adults of working age. Yet recently health experts have raised concerns about workers’ exposures to substances that can cause or worsen asthma in a number of key industries, with progress in preventing the incidence of asthma described as “very disappointing” in some cases. Vicky Powell looks at the efforts currently being made to prevent asthma being caused or made worse by work in future.

Understanding asthma

“Imagine being paralysed by fear as you struggle to breathe, unable to speak, unable to ask for help.” This, says the charity Asthma UK, is what an asthma attack feels like.

In the context of work, the Health and Safety Executive (HSE) distinguishes between occupational asthma and work-related asthma.

Occupational asthma is described as an allergic reaction that can occur when some people are exposed to substances, eg flour or wood dust, in the workplace.

The top cause of occupational asthma is said to be isocyanates — substances which are used across a surprisingly wide range of sectors, most commonly in the construction, manufacturing and motor vehicle repair industries.

Isocyanates are found in paint products and coatings as well as in foam products and industrial floorings. They are also used in a wide range of manufactured goods such as bedding, furniture and packaging as well as in the foundry sector in bonding materials.

After isocyanates, other common causes of occupational asthma include:

  • flour and grain dust (in the baking sector)

  • wood dust

  • solder and colophony (found in the electrical and electronics industries).

These substances are called “respiratory sensitisers” or asthmagens. They can cause a change in people’s airways, known as the “hypersensitive state”.

The HSE says not everyone who becomes sensitised goes on to get asthma but once the lungs become hypersensitive, further exposure to the substance, even at quite low levels, may trigger an attack.

In contrast, work-related asthma or asthma made worse by work is broader and includes substances in the workplace that irritate the airways of individuals with pre-existing asthma. (This includes people who have had asthma since childhood.) Respiratory irritants may trigger attacks in those with occupational asthma or pre-existing asthma, with examples including chlorine, general dust and even cold air.

Asthma UK asked employees with pre-existing asthma what things at work made their asthma worse and the top five answers were dust, stress, chemicals, fumes and perfumes/air fresheners.

Which workers are at risk?

Asthma affects a massive 5.4 million people in the UK. According to Asthma UK, some 1.1 million children (1 in 11) and 4.3 million adults (1 in 12) are currently receiving treatment for asthma, meaning that one in five households must cope with the illness.

Every 10 seconds someone has a potentially life-threatening asthma attack in the UK and every day three people die from an asthma attack.

Occupational asthma is the most common cause of adult onset asthma and makes up between 9% and 15% of cases of asthma in adults of working age.

However, some workers are at greater risk than others. In certain industries, up to 10% of employees develop occupational asthma and research has indicated that the occupations with the highest incidence rates include bakers and vehicle paint sprayers.

The HSE says other occupations with high risks of asthma include solderers, woodworkers, laboratory animal workers, agriculture workers, engineering workers, welders and healthcare workers (where latex and airborne emissions from surgical smoke can play a role).

Recent efforts to tackle asthma at work

Recently, the Bakers, Food and Allied Workers Union asked the Workplace Health Expert Committee (WHEC), set up by the HSE, to investigate the current evidence on the risks to bakers of occupational asthma.

Following the investigation, the WHEC has published a position paper on the subject, concluding that exposures to flour in the UK’s bakeries are, and remain, frequently higher than the level at which occupational asthma would develop; and that the incidence of the disease is “similarly high and unremitting”.

The paper went on to warn that progress on the prevention of occupational asthma in the industry has been “very disappointing,” especially when considered in relation to that in many other industries where workers are exposed to sensitising agents.

The WHEC also pointed out that there are significant barriers to the control of exposure to flour dust and the incidence of occupational asthma in UK bakeries, including the “complex and fragmented” nature of the UK bakery sector.

However, the baking sector is not the only industry facing challenges related to asthma. In May 2017, the British Occupational Hygiene Society (BOHS) launched a new campaign — known as Breathe Freely — to prevent occupational lung disease in the manufacturing sector.

As it launched the new initiative, the Chartered Society for Worker Health Protection shared medical statistics which suggest that workers in the manufacturing sector have rates of occupational asthma that are about three times higher than the all-industry average. In particular, BOHS has identified the sector’s welders as a group at heightened risk of serious lung conditions from inhaling hazardous fumes, gases and dusts. The Society has, therefore, confirmed that the initiative will focus primarily on improving respiratory health protection for welders and asthma is one of the many serious health conditions associated with welding work — along with lung cancer, pneumonia, metal fume fever and chronic obstructive pulmonary disease (which includes conditions such as chronic bronchitis and emphysema).

The Society’s latest initiative follows the original BOHS Breathe Freely campaign to prevent occupational lung disease in the construction industry, which was launched in April 2015 and will continue. During this initial campaign, the Society encouraged construction and other companies to sign up to its Health in Industry (HI) Management Standard, which sets out what good practice looks like in controlling workplace health hazards, of which those which cause asthma are included.

Asthma and good employer practice

In relation to good practice in the prevention of occupational and work-related asthma, the HSE has emphasised there are many things employers can do to reduce the risks.

The HSE’s Charter on Asthma at Work, which is supported by a coalition of employers, employees and health care professionals, sets out five important measures to reduce the impact of asthma in the workplace, based on the following principles.

  • Protecting employees from the causes of occupational asthma and conditions that trigger symptoms of pre-existing asthma at work.

  • Providing a programme of health surveillance and access to up-to-date information on preventing occupational asthma.

  • Ensuring immediate investigation and prompt diagnosis, management and protection for people who develop symptoms of occupational asthma.

  • Ensuring all employees know what to do if a colleague experiences an asthma attack.

  • Ensuring employees understand how to avoid putting themselves and others at risk.

With regard to potential indications for future regulatory focus, the HSE’s new five-year strategy entitled Helping Great Britain Work Well has identified the tackling of ill health as one of its key strategic themes and the prevention of occupational asthma is specifically emphasised within the literature.


Currently, every year up to 3000 people develop occupational asthma because of substances to which they are exposed at work and around half of those with pre-existing asthma find that exposures at work make their asthma worse. Hence, the figure of 3000 is estimated to rise to 7000 a year if cases of asthma made worse by work are included — a disturbing figure which indicates there remains much to be done in order to tackle asthma in the workplace in future.

Last reviewed 20 July 2017