Disease is not necessarily the first thing that would spring to mind when thinking about the risks associated with heating and ventilation contractors but the likelihood of exposure from work undertaken is up in the air. Asbestos, legionella and, most topically, carbon monoxide poisoning are only one breath away.


The dangers of asbestos have been known for many years now. The first legislation was in 1969 although the full ban on the use of asbestos in construction was not until 1992 when the use of white asbestos was added to the ban of blue and brown asbestos from several years earlier. Exposure though is still likely, especially in the heating and ventilation sector where work is carried out in old buildings.

Where exposure is likely employees should be given asbestos awareness training. The need for such is demonstrated by a successful legal case in 2015 where a contractor removed old lagging not realising that asbestos was present and therefore not taking any precautions. This not only left himself exposed to fibres but also the household members when the lagging was carried unprotected through the house.


Legionella is the term for a group of bacteria which cause illnesses including Legionnaire’s disease (pneumonia like) and Pontiac fever (flu like). The bacteria needs organic matter to provide nutrients if it is to multiply and this can include rust, sludge, scale and algae. Legionellosis (all illnesses resulting from legionella) is contracted by inhaling infected water droplets and therefore can be a risk inherent with water based air-conditioning. The main risk is from poor design and/or maintenance. The use of air-cooled refrigerant based systems removes the risk entirely.

Carbon Monoxide

Carbon monoxide is the silent assassin. Colourless, odourless and tasteless, it is very difficult to detect and, according to NHS analysis in 2011, this results in 4,000 visits to A&E, 200 hospitalisations and 50 deaths a year, and this is just England and Wales. Symptoms include nausea, headaches and dizziness but prolonged exposure can lead to death.

Carbon monoxide is produced when carbon based fuels do not burn fully due to a lack of oxygen. The main cause of such poisoning is faulty heating or cooking equipment through either not being properly installed or maintained or poor ventilation.

The use of wood and coal burning systems is a lot less than it used to be so the main heating culprit these days is gas. Under the Gas Safety (Installation and Use) Regulations 1998 for a firm to legally undertake gas work they must be on the Gas Safe Register (previously CORGI). However, there are many illegal gas fittings firms and it has been estimated that 5 million homes are at risk in the UK due to unsafe gas work by illegal fitters.

The exposure for all three of these diseases is present in the industry but can be dramatically reduced by training, risk awareness, risk assessments and Gas Safe registration.

Have you got the right cover?

Exposure cannot totally be removed however and that is why suitable insurance for employers’ liability, public / products liability and professional indemnity is essential.

A standard liability insurance with most insurers will have an asbestos exclusion. This will be a full exclusion on the public / products liability but because of compulsory legislation, usually there will be an inner limit of £5,000,000 for asbestos claims under the employers’ liability section. Under such standard cover there would not have been protection for the 2015 claim mentioned above because the claim for any asbestos related disease to the third party family members would be excluded.

It is possible to obtain an accidental asbestos discovery extension to public liability insurance which should be sufficient unless asbestos removal is also undertaken in which case a full asbestos cover would need to be arranged.

Legionella may be excluded under a public / products liability insurance but it should be possible to arrange an extension for this cover provided precautions and risk assessments are undertaken.

There is no standard UK exclusion for carbon monoxide poisoning so there is no need to purchase an extension. It is possible that it may be construed as pollution and this will depend on how pollution is defined in the policy e.g. is there a specific reference to noxious fumes. However, whilst UK public / products liability policies do have a pollution exclusion, pollution arising from a sudden, identifiable, unintended and unexpected incident occurring at a specific time and place is covered by most policies. If not regarded as explosion then carbon monoxide poisoning should be regarded as a standard public liability or products liability claim.

How Miles Smith Can Help

Our building and engineering services contractors combined insurance is aimed at heating and ventilation contractors. The public / products liability section includes extensions for accidental asbestos discovery and legionella, both for a limit of £1,000,000 in the aggregate.


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