One in three people over the age of 60 suffer from old age deafness, and two in three over 70 years. Loud noises damage hearing. The cochlea hairs move so violently that they bend or snap off. A sudden loud noise like gunfire or an explosion can damage the cochlea. Long term exposure to loud noise is also a problem.
Many people working in noisy environments like shipyards suffer damage to their hearing.
In 1974 a law was passed limiting worker's exposure to noise and making the provision of ear protection compulsory. Some drugs can damage the cochlea, especially streptomycin, or excessive use of aspirin. A baby may be born deaf because of cochlea damage before birth as the result of infections during pregnancy. Mumps and meningitis can damage the cochlea. Meniere's disease also causes sensori-neural deafness.