The company has a 5 star ranking system for each category but I could not find information on their website about the corresponding decibel level. The National Council on Fireworks Safety, Inc. has a list of Recommended Safety Tips with no mention of hearing safety. Which is a shame because it is a missed opportunity to educate a lot of people.
Fireworks can be as much as 140 dB depending on your distance from them. And generally the bigger the firework the bigger the noise. Professional fireworks may be louder but they are also farther away from you.
I found that Dynamite Fireworks had more information about hearing safety on their "How loud are different fireworks?" page. I found their information both very detailed and accurate. I particularly like this gentle reminder:
"Since the decibel level to which you are exposed varies according to how far away you are, it only makes sense to step back several feet after lighting a consumer firework. The World Health Organization recommends that adults be exposed to no more than 140 decibels, which can be achieved by repositioning yourself a bit. Keep children well away from the spot where the fireworks will explode, as they should be exposed to no more than 120 decibels. It is best to keep infants away altogether, as they are highly sensitive to the physical effects of sound pressure."
Seriously, check out their page, share with others! They have lots of social media connections.
I also recommend the Noisy Planet website, from the National Institute of Health, for more resources on hearing damage, how to prevent it and how to engage your students in the discussion.
So what can you do? Well at a minimum plug your ears. A better bet is cheap foam ear plugs that can reduce it down 20+ dB. And the best option is to wear professional ear protection. If anyone teases you, just mouth "I can't hear you."