Strictly speaking, is it appropriate? Well, that really depends on what your contract / the employee manual / whatever says. If you were hired as a programmer and there's no clause anywhere that can be considered to include this, then it's most likely not appropriate. Although, unless it's serious enough that you're willing to possibly lose your job and take legal action over it, 'appropriate' probably doesn't really matter. If you are serious about it, you should definitely go and speak to a lawyer specializing in labour laws before you do too much.

It doesn't sound like you have much of a problem with the basic idea, so it's probably best left alone, at least until you see where it goes.

If you did have a problem with the basic idea, you could certainly take this up with management beforehand, but expect to lose some respect over it and, if management isn't particularly nice, you may end up being asked to do it anyway, which would likely put you in a difficult spot.

If you find that the distraction affects your programming productivity, or it's just too often, I'd say this is definitely something to talk with management about. Perhaps arrange a meeting with management and say something like "While I don't mind helping out with tasks not related to my job occasionally, I feel that the frequency at which I'm currently required to help out is causing too much of a distraction for me to be particularly productive as a programmer". From here, possibly try to arrange fixed times to perform this work, or whatever would suit both you and the company, although a likely result would involve you not performing these tasks at all any more.

Both of my above points would be overshadowed by you being able to put up a convincing argument that there's a significant risk of injury (to you personally, or in general) from performing these task. I imagine (legitimate) hazardous working conditions could end up in a law suit that would be fairly easy for an employee to win, so companies may tread lightly when it comes to this (note - I'm not a lawyer).