It shouldn't be 'how things are done', but unfortunately, I think there's a certain contingent of people out there who aren't as savvy or concerned about the proper way to handle information like this.
I've filled out some forms recently that asked for cell phone. I don't put it on there. I want it used for emergencies only, or when *I* deem that I want to use it. Plus, I can see it getting on some kind of a list and getting those obnoxious calls and texts about lowering my credit rating or whatever.
One time, back in the early days of cell phones, I had a plan that had a per-minute charge. I gave the number to my then-boss (small company, and she was married to the owner) for emergencies. I was driving somewhere and she proceeded to call my phone and gabbed about nothing significant for 20 minutes! If I remember right, I think I expensed the charges for that call.
I would contact the project heads and ask them about this, and why they put it on the list that went to everyone. Explain that you never thought your information would go out to everyone in the group; if you had known that, you wouldn't have given that information or perhaps wouldn't have even volunteered. Ask them to redistribute the list without your phone number. Yeah, I know that won't fix the list that already is out there, but perhaps if they have to do a bit of work, they'll think twice about giving out people's information in the future without a specific disclaimer.