3. Excess heat

Most vulnerable: All age groups

This category includes threats from excessively high indoor air temperatures.

Effects

• Cardiovascular strain and trauma
• Dehydration

4. Asbestos and Manufactured Mineral Fibres

Most vulnerable: All age groups

This category covers the presence of, and exposure to, asbestos fibres and manufactured mineral fibres within dwellings.

Effects

The health risks from asbestos exposure are associated with inhalation. Risks from ingestion and skin contact are minimal. The inhalation of asbestos fibres can cause pleural disease (pleural plaques and fibrosis), lung cancer and mesothelioma (cancer of the pleura, the lining around the lung, or, less frequently, cancer of the peritoneum).

5. Biocides

Most vulnerable: All age groups

This category covers threats to health from those chemicals used to treat timber and mould growth in dwellings. While biocides include insecticides and rodenticides to control pest infestations (for example cockroaches, rats or mice), these are not considered for the purposes of the HHSRS .

Effects

Biocides are intended to prevent growth or development of insects, fungi, moulds, and bacteria, or kill those already present. The potential for harm to human health varies depending on the biocide. The main health risk is from inhalation, although skin contact and ingestion may also be an issue, particularly for small children.

6. Carbon monoxide and fuel combustion products

Most vulnerable: Those over 65

This category includes hazards resulting from the presence of excess levels in the atmosphere within the dwelling of:

• Carbon monoxide
• Nitrogen dioxide
• Sulphur dioxide
• Smoke

Effects

• At high concentrations carbon monoxide can cause unconsciousness and death
• At lower concentrations, it causes a range of symptoms from headaches, dizziness, weakness, nausea, confusion, and disorientation, to fatigue
• All symptoms which are sometimes confused with influenza and sometimes with depression
• In people with ischaemic heart disease, it can result in episodes of increased chest pain
• Carbon monoxide may impair foetal development

7. Lead

Most vulnerable: Children under 3

This covers the threats to health from the ingestion of lead.

Effects

Lead is a heavy metal, which, when ingested accumulates in the body, and has toxic effects on the nervous system, cognitive development and blood production.

8. Radiation

Most vulnerable: Those between 60 and 64, who have had lifetime exposure to radon

This category covers the threats to health from radon gas, primarily airborne, and also radon dissolved in water.

Effects

Radon gas is the second most important cause of lung cancer after smoking, and most radon exposure occurs at home. As radon is soluble in water, it can be ingested, resulting in the organs of the gastrointestinal tract receiving the largest dose.

9. Uncombusted fuel gas

Most vulnerable: All age groups

This category covers the threat of asphyxiation resulting from the escape of fuel gas into the atmosphere within a dwelling.

Effects

Fuel gases can cause asphyxiation. This occurs when the fuel gas builds up within the dwelling, displacing the air to such an extent that the occupants are unable to obtain sufficient oxygen to breathe.

10. Volatile organic compounds

Most vulnerable: All age groups

Volatile organic compounds are a diverse group of organic chemicals including formaldehyde, which are gaseous at room temperature, and are found in a wide variety of materials in the home.

Effects

Most individual volatile organic compounds that may be found in dwellings have no reported health effects. However, some may cause short term irritation and allergic reactions to the eyes, nose, skin, and respiratory tract. Higher concentrations can result in headaches, nausea dizziness and drowsiness. Formaldehyde can be a particular problem, although sensitivity varies. Allergy sufferers and asthmatics are most vulnerable, and may react to exposure at levels below those that would affect others.