Radon, radiation & stythe gas

Radon is a radioactive gas that which is invisible, has no odour or taste and requires special equipment to detect. Radon is generated from the decay of radium which is found in a number of rocks, particularly granites formed originally from volcanic processes. Typically, areas located over such areas can have higher levels of radon gas which can ingress into buildings, especially where there is little superficial cover (clays/soils).

The radon level in the air we breathe outside is very low but can be higher inside buildings where it cannot disperse.

The British Geological Survey and UK Health Security Agency (formerly Public Health England) produce radon gas risk maps for the UK which identifies risks in six classes with three categories for the inclusion of protection in new dwellings and extensions where possible:

• 0 - <1% - no radon gas protection required in new builds
• 1 - <3% - no radon gas protection required in new builds
• 3 - <5%- basic radon gas protection required in new builds
• 5 - <10%- basic radon gas protection required in new builds
• 10 - <30%- full radon gas protection required in new builds
• 30 - <100%- full radon gas protection required in new builds

The numbers are the percentage of properties within any given area that are at risk of exceeding the radon “action level” of 200 becquerels per cubic metre.

The responses in different areas are either; nothing, basic radon protection (gas membrane) or full protection.
The Building Regulations require that radon gas protection is included in new buildings which can either comprise “basic protection” in the form of a gas resistant membrane or “full protection” including a membrane and any other protection elements (ie sump pumps, gravel trenches, no fines gravel ventilation layer etc.) where the predicted radon levels are higher.

The BGS produce two resolutions of radon map – a detailed one with a 25 metre grid resolution and an indicative on which takes the highest predicted radon level within a 1km grid square and makes that who 1km2 as that highest level. The indicative mapping is available online by clicking here.

You can check if your property or workplace is in is a radon affected area by carrying out and address/postcode search by clicking here.

Following the Chernobyl nuclear power accident in 1986, the council continues to measure background radiation in order to monitor changes and track those caused by nuclear incidents.

Using this method, we were able to identify that in 2011 there was no health risk to UK residents from the release of radioactive material in a Japanese nuclear power plant.

• For further information, click here.

Many gases can be emitted from the ground from historic and contemporary uses and these can accumulate in building and present a risk to occupants and users.

Mine Gases

Historic mines can be a source of various gases and a reservoir for them which can be forced to the surface when there a significant atmospheric air pressure drop and when there is mine water recharge.

One of the main “gases” of concern is “Stythe Gas”, also known as ‘black damp’, which is air containing depleted oxygen caused by the oxidation of coal and timber left behind in old deep coal mine workings. It can be fatal where the oxygen content is particularly low but can cause a number of health issues at concentrations below 19 percent.

The risk is greatest when there are sharp drops in atmospheric pressure, leading to former deep mines ‘breathing out’ gases. This link was first established in the UK following the house explosion at Loscoe in Derbyshire in 1986.

Other mine gases such as ‘fire damp’ (methane) can also be as dangerous and, in some cases when the concentration is high enough, it can be explosive.

Mine gases can come to the surface through old mine entries and boreholes or through cracks in the underlying rock. It can collect in places like unventilated downstairs rooms and cellars.

The Coal Authority is a government body with a statutory responsibility to deal with surface hazards from past coal mining activities.

• Click here for more information about coal authority 

Mine gases - how to act

• If you think you’re being affected by mine gases, contact the Coal Authority’s 24-hour emergency call out service immediately on 0800 288 4242.

• If in doubt, contact the emergency services on 999

For developments in the Coal Authority High AND Low Risk Developments Areas, the Environmental Protection Team recommend gas protection in new buildings to the Local Planning Authority to a minimum of Characteristic Situation 2 (CS2) as detailed in BS8485:2015+A1:2019 (Code of Practice for the design of protective measures for Methane and Carbon Dioxide ground gases for new buildings).

Landfill Gases

Gases can be produced from landfills where putrescible wastes have been included. This tends to be more common with historic landfills where recycling and reuse of particular wastes was less common and where landfill gases were not recovered for the production of energy as is the case in modern landfills.

There are a number of historic landfills in Northumberland and data supplied by the Environment Agency on these landfills can be found bt clicking here.

As a “rule of thumb”, almost all gas is produced within 20 years after waste is dumped; however, small quantities of gas may continue to be emitted from a landfill for 50 or more years.

The only current domestic waste landfill in Northumberland is the SUEZ Recycling and Recovery UK site at Ellington Road, Ashington NE63 9XS.

Northumberland County Council Waste Services may have responsibility for some historic landfills either in respect of land ownership and/or monitoring.

Get in touch with the council if you have any pollution issues you think we can assist with.

For more information, please contact us here.