The symptom of loud ringing in the ear that you are describing is known as tinnitus. This can absolutely be one of the first signs of irreversible damage to the ears and the start of hearing loss. The encouraging thing is that it is not constant, but rather comes and goes, and that you do not otherwise feel that you have lost hearing. The first and most important step is to beginning to wear hearing protection on your job to prevent further damage to your hearing. All employers are required by law to provide adequate on the job protection to their employees. Subsequently, the next best step is probably to have a formal audiological evaluation (your primary care doctor
can refer you) to see what shape your hearing is in right now. As always the diagnosis and the management of your particular concerns will require a physical examination by your personal physician. Setting up an office visit with your primary care doctor as soon as possible is recommended.