To ask the Secretary of State for Wales how many homes the National Radiological Protection Board has surveyed for radon in each year since 1989 in (a) postcode district SA, (b) Wales and (c) the United Kingdom.
The number of homes surveyed for which results are available are shown in the following table:
| Year | Postcode SA | Wales | United Kingdom |
| 1989 | 110 | 390 | 8,200 |
| 1990 | 25 | 140 | 3,500 |
| 1991 | 90 | 430 | 71,000 |
| 1992 | 7 | 73 | 23,000 |
| 1993 | 18 | 110 | 31,000 |
To ask the Secretary of State for Wales what is his best estimate of the number of houses in postal district SA whose occupants are exposed to radon gas in concentrations of (a) 0 to 25 becquerels per cubic metre, (b) 26 to 50 becquerels per cubic metre, (c) 51 to 100 becquerels per cubic metre, (d) 101 to 200 becquerels per cubic metre and (e) more than 200 becquerels per cubic metre.
The research completed to date does not allow the estimate requested to be prepared.