HC Deb 25 July 1991 vol 195 cc755-6W
Mr. Steen

To ask the Secretary of State for the Environment what research has been undertaken into the effectiveness of the removal of radon gas from newly constructed dwellings; and if he will outline the results of the research.

Mr. Yeo

The Building Research Establishment is undertaking research into the practical building problems and the effectiveness of measures to combat radon gas in newly constructed dwellings. The findings of the research are being taken into account in revised guidance to support the Building Regulations, but final results will not be available until next year.

Mr. Steen

To ask the Secretary of State for the Environment what evidence he has relating to the effect of radon gas on the life expectancy of people living in and around Dartmoor.

Mr. Baldry

The evidence for the health effects of radon gas in Dartmoor and elsewhere is provided by the National Radiological Protection Board. In particular, I refer my hon. Friend to the "Documents of the NRPB", Vol. I, Nos. 1 and 4, 1990, copies of which are in the Library of the House.

Mr. Steen

To ask the Secretary of State for the Environment if he will publish the new maps being prepared by his Department indicating where radon is to be found at its highest levels.

Mr. Baldry

Yes.

Mr. Steen

To ask the Secretary of State for the Environment if he will outline the research evidence lying behind the setting of an advisory level of 200 becquerels in newly constructed dwellings.

Mr. Baldry

The research evidence requested is set out in the National Radiological Protection Board publication "Documents of the NRPB", volume I, No. 1, 1990. Copies were placed in the Library on publication.

Mr. Steen

To ask the Secretary of State for the Environment what method of site inspection he proposes to introduce to discover(a) whether radon is present, (b) in what quantities and (c) whether it is potentially dangerous to health.

Mr. Baldry

My Department funds the National Radiological Protection Board to carry out free surveys of the levels of radon in houses using passive etched-track detectors over a period of at least three months. The NRPB advises the householder of the danger to health according to the recorded radon level. There is no reliable method of predicting radon levels from site measurements before house construction.

Mr. Steen

To ask the Secretary of State for the Environment (1) what proposals he has to introduce under section C2 of the Building Regulations 1985 mandatory requirements for methods of construction so as to prevent the entry of radon gas into newly constructed dwellings;

(2) what advice he is giving building control officers with regard to the reduction of radon gas to less than 200 becquerels.

Mr. Yeo

Regulation C2 of the Building Regulations 1985 requires precautions to be taken to avoid danger to health caused by substances found on or in the ground to be covered by the building. Interim guidance relating to radon was produced in June 1988 to support this requirement. A revised approved document for part C which specifically refers to radon will be published later this year, and this will be supported by more detailed guidance on methods of construction to limit the entry of radon gas into newly constructed dwellings.

Mr. Steen

To ask the Secretary of State for the Environment what is the average annual dose of radon received by people in the United Kingdom, expressed in terms of milliSieverts; and what is the average in Devon.

Mr. Baldry

The average annual dose of radon received by people in the United Kingdom is 1 milliSievert effective dose equivalent. In Devon, the annual average dose is 3.5 milliSieverts.

Mr. Steen

To ask the Secretary of State for the Environment if he will make a statement about the migration of uranium daughter radionuclides in natural sediments; and to what extent there are similar elements with regard to radon gases in rock formations.

Mr. Baldry

The solid radioactive species in the uranium decay series do not migrate in dry rock formations. However, radon, which is a noble gas, readily migrates through fissured rocks, soils and sediments.