The manufacturer of the paper, i think polymax is kodak (correct me if i'm wrong) usually puts a piece of paper inside the box of paper giving you the data for the photo paper, including develop stop fix and wash times, and if you look closely, they usually say something like red safelite 102 or amber safelite 321 up to 4 feet away is safe.
Hopefully this helps, and i agree with glennfromwy, that from my personal experiences, red safelites never fog my paper.
I was always under the impression that red is the "safest" safelight.
The best bet is to do a test. Set an opaque object on the paper and expose it to your safelight for a period of time that is, say, three times longer than the paper would be out under normal circumstances. Develop it, and see if you made a pictograph. If you didn't, your safelight is safe.