"In general, sounds above 85 are harmful, depending on how long and how often you are exposed to them and whether you wear hearing protection, such as earplugs or earmuffs.
Harmful Noise Levels - My Health Alberta - Government of Alberta
" With extended exposure, noises that reach a decibel level of 85 can cause permanent damage to the hair cells in the inner ear, leading to hearing loss."
Dangerous Decibels ยป Noise Induced Hearing Loss
The upper exposure action value is set at a daily or weekly average noise exposure of 85 dB, above which the employer is required to take reasonably practicable measures to reduce noise exposure, such as engineering controls or other technical measures. The use of hearing protection is also mandatory if the noise cannot be controlled by these measures, or while these measures are being planned or carried out.
Finally there is an exposure limit value of 87 dB, above which no worker can be exposed (taking hearing protection into account).
Noise: Frequently asked questions (FAQs) - HSE