Carbon monoxide (CO)

What you need to do

The law says you must identify any activities that may expose workers or the public to carbon monoxide (CO) gas, and manage any risk accordingly.

All gas work carried out in the home and in certain commercial premises should be done by a Gas Safe registered engineer.

There are three main ways in which construction work can interface with CO gas issues:

• Site worker and security staff facilities
• Refurbishment work on existing buildings
• Gas Safe Register for gas engineers

What you need to know

Site gas-fired appliances, refurbishment work on existing buildings and work on gas systems have all lead to deaths from CO poisoning.

CO is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of carbon-based fuels, including gas, oil, wood and coal.

When the fuel does not burn properly, excess CO is produced. When CO enters the body, it prevents the blood from bringing oxygen to cells, tissues, and organs.

Early symptoms of CO poisoning can be confused with food poisoning, viral infections, flu or simple tiredness. Symptoms to look out for include drowsiness, headaches, breathlessness and nausea.

Site worker and security staff facilities

Inadequately ventilated liquefied petroleum gas (LPG) cookers and heaters can produce CO gas. Flammable gas may also escape from leaking cylinders.

Site workers and night security staff have died from CO poisoning on construction projects where such gas-fired appliances have been used in site welfare or rest facilities.

Using properly maintained electrical equipment can eliminate the risks associated with LPG heaters. If LPG is used you can reduce the risks by:

• using and storing the cylinders in safe, well ventilated places outside the accommodation (including overnight) or in purpose-built ventilated storage areas;
• ensuring that appliances have been properly installed, checked and maintained by a competent person;
• providing adequate combustion ventilation with  fixed grilles at high and low level;
• checking that the ventilation provided is not blocked, e.g. by newspaper or rags in cold weather to “stop draughts”;
• checking that cylinders are properly turned off when not in use; and
• using wall or ceiling mounted carbon monoxide detectors.

Refurbishment work on existing buildings

Members of the public have died from CO poisoning after refurbishment work e.g. roof work, has disrupted gas flues or ventilation systems, causing CO to build up in occupied premises.

The impact of refurbishment work on existing gas-fired systems must be identified during the planning stage and managed throughout the project. 

A competent gas engineer should be involved where there is any likelihood that refurbishment work will affect gas fired systems.

Gas Safe Register for gas engineers

Every year, approximately 25 people die from carbon monoxide poisoning caused by appliances and flues that have not been properly installed or maintained. 

All gas work carried out in the home and in certain commercial premises should be done by a Gas Safe registered engineer. Gas work includes: installing, repairing or servicing a gas boiler and installing or repairing a gas fire, gas cooker or hob. 

The Gas Safe Register is the only gas engineer registration scheme approved by HSE under the Gas Safety (Installation and Use) Regulations 1998.

All gas engineers wanting to undertake domestic and certain other gas work need to be registered with the Gas Safe Register.

For more information visit www.gassaferegister.co.uk