Conduct research, and carry out trials using ANR headsets and ear protection devices, collaborating with BALPA. They are already doing so.
Seems a poor decision to me: anyone earning a Norwegian Pilot's salary, who can't figure out that two Makilas sitting above your head doing 31,000 rpm for hours on end might be a bad thing for your ears, and who can't be bothered to spend $500-800 on an ANR headset, needs their head examining, not having large sums of cash dished out.