When the person responsible for a nuclear activity carries out compulsory measurements of environmental radioactivity in order to contribute to the monitoring of exposure of the population and the environment, he shall have these measurements carried out by a laboratory approved under the conditions laid down in article R. 1333-26 or by the Institut de radioprotection et de sûreté nucléaire. It shall ensure that the results are transmitted to the national network for environmental radioactivity measurements mentioned in article R. 1333-25.