Occupational Asthma and Work Related Asthma
The Health and Safety Executive site that there have been an estimated 1,500 to 3,000 new cases of occupational asthma each year. This rises to 7,000 cases a year if you include asthma made worse by work (work-related asthma). Recent figures suggest a slight decrease.
Asthma is a condition that affects the airways - the small tubes that carry air in and out of the lungs. If you have asthma your airways are almost always sensitive and inflamed. When you come in to contact with something you are allergic to, or something that irritates your airways they will become narrower, making it harder to breathe. The muscles around the walls of your airways tighten. The lining of the airways becomes inflamed and starts to swell and often sticky mucus or phlegm is produced. This will lead to you experiencing asthma symptoms such as a cough or wheeze, shortess of breath, a tight feeling in your chest.
What can cause asthma?
Asthma can start at any age. Some people get symptoms during childhood which then disappear in later life. Others develop 'late-onset' asthma in adulthood, without ever having had symptoms as a child.
- asthma can be inherited
- late-onset asthma may develop after a viral infection
- irritants found in the workplace may lead to a person developing asthma
Occupational asthma
Occupational asthma is caused by workers breathing in substances at work that produce a hypersensitive state in the airways triggering a response. Not everyone who becomes sensitised goes on to get the clinical disease but once the lungs become hypersensitive further exposure to the substance, even at quite low levels, may provoke an attack.
Work-related asthma
Work-related asthma is broader. It includes substances in the workplace that irritate the airways of individuals with pre-existing conditions. Respiratory irritants may provoke attacks. Examples include chlorine, general dust and even cold air. In this case, the individual does not become sensitised to that specific agent, but the attack is still work-related.
Symptoms of asthma of whatever cause, include attacks of wheezing, coughing chest tightness or shortness of breath. The symptoms can develop right after exposure. But sometimes symptoms appear several hours after exposure, possible at night, and so any link with workplace activities may not be obvious. Some sufferers become so disabled that they cannot work again. Other associated conditions are rhinitis (sneezing/runny nose) and/or conjunctivitis (itchy and inflamed red eyes).
Causes of occupational asthma
There are many causes of occupational asthma and work related asthma. Fourteen have been prescribed as resulting in industrial diseases:
- Isocyanates - modern synthetic finishes
- Platinum salts
- Epoxy resin curing agents
- Colophony fumes
- Proteolytic enzymes
- Animals and insects in laboratories
- Flour and grain dust
- Antibiotic manufacture
- Cimetidine used in manufacturing cimetidine tablets
- Hard wood dusts of cedar, oak and mahogany
- Ispaghula used in the manufacture of laxatives
- Caster beacarbon dust
- Ipecacuanha used in the manufacture of tablets
- Azodicarbonanide used in plastics
Jobs and activities using substances linked to developing a respiratory disease
- Vehicle spray painting
- Foam manufacturing
- Bakers / flour mill workers
- Agricultural
- Dock handling
- Milling activities
- Healthcare
- Offshore
- Papermaking
- Agricultural
- Healthcare
- Electrical and electronics industries
- Animal research laboratory and educational activities
- Moulding and adhesive bonding
Substances that can cause respiratory disease and asthma
- Isocyanates
- Flour dust
- Grain dust
- Glutaraldehyde
- Wood dust
- Latex (natural rubber latex) eg gloves
- Solder / colophony rosin - solder fluxes from the fumes
- Laboratory animals - airborne proteins from animal fur and urine
- Glues and resins - epoxy resins and hardeners especially anhydride hardening agents
Other substances that have been known to cause occupational asthma
- Alpha amylases enzymes that change starch into sugar. Used in flour milling and bread baking. Also used in detergents, animal feed, textile processing and brewing
- Azodicarbonamide used in the expansion of polymers in the rubber and plastics industries
- Bromelains enzymes within the fruit, stem and leaves of the pineapple. Used pharmaceutically as an aid to digestion and as an anti-inflammatory agent
- Carmine an insect-derived dyestuff. Used for cosmetic and pharmaceutical dyeing and as a food and drink colouring
- Castor bean dust castor oil is used in paint, varnish, hydraulic fluids, printing inks, nylon, plastics and cosmetics and hair oils
- Cephalosporins antibiotics similar to penicillin
- Chloramine-t a disinfectant with antiviral, bactericidal and fungicidal properties. Highly reactive with proteins
- Chloroplatinates and other halogenoplatinates platinum salts produced during the refining of platinum metal and the manufacture of catalysts and electrodes
- Chromium (vi) compounds present in stainless steel welding fume and cement and used in electroplating
- Cobalt (metal and compounds) present in the hard metal production and diamond polishing industries
- Cockroach material dust from the bodies, eggs, saliva, faeces and cast skins of cockroaches
- Coffee bean dust dust from the processing of coffee beans
- Cow epithelium/urine dust from cow hair and dander
- Crustacean proteins from the processing of prawns, crabs, shrimps and lobsters
- Diazonium salts used in the manufacture of dyes, photocopier paper and fluorine polymer production
- Egg proteins from the processing of egg products or the use of eggs in glazing bakery products
- Ethylenediamine a corrosive chemical with an irritating vapour used in the printed circuit board and metal finishing industries. Also used in epoxy coatings and resins and in the manufacture of pharmaceuticals
- Fish proteins from the use of automated machines to gut various species of fish
- Flour dust finely ground particles of cereals or pulses, and additives in the final product mix
- Glutaraldehyde a chemical disinfectant and biocide used as a cold sterilant of medical and surgical instruments. Also used in the oil and gas industry for the inhibition of corrosion causing bacteria
- Some hardwood dusts a general term covering a wide variety of wood dusts.
- Henna a plant derived dye that is used to colour hair and skin
- Isocyanateswidely used in manufacture of polyurethane foams, plastics, coatings, varnish, two-pack paints and adhesives
- Ispaghula a laxative obtained from the dried ripe seeds of plantago ovata
- Laboratory animal excreta/secreta mainly from rodents (rats and mice). Also small mammals and insects
- Latex natural rubber latex is from the hevea braziliensis tree. Health care workers are particularly susceptible through the use of latex gloves.
- Maleic anhydride used in the manufacture of polyester resins, oil additives and maleic acid
- Methyltetrahydrophthalic anhydride used in the production of epoxy resins used in the manufacture of special application plastics
- Nickel sulphate used in the electroplating industry and the production of hard metal
- Opiates a group of drugs derived from opium - includes morphine, heroin and codeine
- Papain an enzyme from the fruit of the paw-paw tree. Used for meat tenderising, clearing of beer, treatment of wool and silk and in food, cosmetic and pharmaceutical products
- Penicillins a large group of natural or semisynthetic antibiotics
- Persulphates strong oxidising agents used to enhance the action of peroxide hair bleaches
- Phthalic anhydride used in the manufacture of plasticisers, resins, dyes, pesticides and pharmaceuticals
- Piperazine used in the manufacture of dewormers in veterinary and human medicine; the manufacture of hot melt adhesives; and the manufacture of a corrosion inhibitor for the offshore oil industry
- Psyllium a laxative obtained from the plantago species
- Reactive dyes have a high degree of wet fastness. The reactive dye molecule fixes itself to natural materials such as cotton, silk, wool or leather by a strong chemical bond
- Rosin-based solder flux fume rosins are natural resin derived from pine trees. Most commonly, gum rosin (colophony) is the form used by solderers
- Some softwood dusts a general term covering a wide variety of wood dusts derived from mainly coniferous trees. Occupational exposure to cedar dusts is associated with the development of asthma
- Soybean dust soybean, a very rich source of protein, comes from the leguminous plant glycine max. It is used as the whole bean, the oil and the meal. Soybean flour is used alone or mixed with other flours
- Spiramycin an antibiotic manufactured as a fine white powder
- Storage mites found in stored foodstuffs such as hay and grain in conditions of high humidity
- Subtilisins enzymes used in the manufacture of detergents and animal feeds. Also food & leather processing
- Tetrachlorophthalic anhydride used in production of epoxy resins for manufacture of plastics, paints and electronic components
- Trimellitic anhydride used in production of plasticisers, wire enamels, surface coatings and wall and floor coverings
