With my kiddo's SPD it's the sounds of the toilet and the hand dryers. It's not a fear of harm or being sucked in, the sounds to her ARE physically painful.
And you can't really desensitize them to the sounds because along with the sounds is the fear that they MIGHT come at ANY time, so it's often not just you flushing the toilet or using the hand dryer, but anyone else who MIGHT.
So you do baby steps, use headphones, or music (lately if my DD hears a song on my phone she will be brave), and lots of incentives and know that a random loud flush or those super powered, super loud hand dryers can set you back to square one at any time. My DD3 is back in diapers when we're out because she's literally terrified, but at home she's 100% potty trained. We also have square rooted in our city neighborhood every place without auto flushers and either without hand dryers or with only the small, quiet ones.
The best I can explain it to someone is I'm severely dyslexic. I've learned to compensate, I'm a writer in fact, but I will always see words and other things backwards/wrong. SPD is sort of like she hears things backwards/wrong. A sound to me that is annoying, not even a loud one necessarily is completely jarring and terrifying to her. She can't block it out like other people can or learn to expect it. The expectation in fact makes for greater fear.
So my job, the OT we focus on, is to teach her tricks to compensate and we do all the time. She's brilliant and WANTS things to not bother her. She wants to be out of diapers so she can take ballet class, but the best/closest school where her friends all go has auto flushers and hand dryers. It's a work in progress.
Music, earphones, and avoidance helps with sounds. She has other SPD things which she has learned to deal with. Textures on clothing and food, smells, being touched by strangers, other sounds (a baby crying really gets her, gruff voices, motorcycles, ambulances, some music, angry people yelling, whispering), being overwhelmed by crowds, etc.
Thanks again to everyone for a current list. Her knowing if there's something there is extremely helpful!
