Defence Minister Andrew Murrison said a timetable for dealing with Dalgety Bay had now been agreed between the Scottish Environmental Protection Agency (SEPA) and the Ministry of Defence (MoD).
Mr Brown has been calling for a clean-up at the bay after radiation was detected. He has said it was caused by the Ministry of Defence breaking up hundreds of planes after the Second World War.
He has raised the issue more than any other in his rare Commons appearances since leaving office, with a series of adjournment debates and written questions to ministers.
In the latest written answer, Dr Murrison said: "I will write to you shortly with the detail of the time-lines for the further scientific risk assessment and other work necessary to identify an appropriate long term solution at Dalgety Bay.
"This timetable has been agreed between SEPA and the MoD. Once work on identifying the most appropriate long term management option has concluded, we expect to play an active part in supporting SEPA in their engagement."