The Hard Hat Communications System consists of a bone conduction headset and a speaker microphone. The headset attaches to the rear of a safety helmet (which must be of a type which has a hard adjustable ratchet assembly). A bone conduction microphone sits against one side of the user's head and a bone conduction speaker against the other. The bone conduction microphone allows normal speech when the user is wearing a respirator or other breathing equipment and/or is in a high ambient noise environment. The bone conduction speaker allows the user to hear audio from a portable radio whilst wearing hearing protection. The headset connects to a portable radio via the speaker microphone. With no headset connected, it functions as a normal speaker microphone. With the headset connected, the internal microphone is disabled and the bone conduction microphone in the headset takes its place. If the user is not wearing hearing protection, he will hear the speaker microphone directly and will perceive some sound from the bone conduction speaker. If hearing protection is being worn, he will hear clearly through the bone conduction speaker.