a workplace injury rendered my dad unable to hear women

My dad has worked in factories all of his life. Before safety equipment was supplied by the workplace, he'd often come home complaining of headaches. He'd also come home with all sorts of injuries such as cuts and bruises and the occasional concussion.

Of the longer lasting injuries my dad has suffered, his hearing loss has been the worst. Dad's employer deals in fabricated metal products. The metal cutters emit high pitched noise all day and the extractor fans in the spray paint booths and the enamel ovens emit a low hum all day. Both of these types of noise are considered dangerous in the workplace. The high pitch because it causes damage to hearing, which is what happened to dad. We used to joke that he couldn't hear women's voices. There was a character in one of his favourite TV shows (Will and Grace) who had a particularly high voice, and he said he couldn't hear any of her lines.

When dad eventually had his hearing tested, he was missing a whole range of hearing. The doctor attributed this to the tools used in his workplace.