Wrong Insulation on Steam Pipes?

Short time lurker, first post.

I have a gas-fired one-pipe steam system and had the asbestos insulation removed from our steam pipes fourteen years ago and never bothered to reinsulate the pipes. From reading this site I have learned that this not an uncommon situation.

So, a few weeks ago, I finally reinsulated the pipes. Unfortunately, I think I used the wrong stuff. I used polyethylene insulation (http://www.tundrafoam.com/tundra/pipe_index.html), which I'm now reasonably sure is intended for hot water pipes but not steam pipes. I have two questions: 1) is the polyethylene insulation safe, and 2) is it reasonably effective? I believe it's rated for something like 215 degrees, so it has almost no margin. The outside of the insulation feels warm/hot to the touch when the system is distributing steam, so I know I'm still getting some heat loss. However, the basement feels a lot colder than it did before I installed this insulation, so I believe it's doing something.

Should I scrap this insulation and install fiberglass, or move on to the next series of problems (venting the mains, replacing radiator vents, cleaning/replacing pressuretrols, etc.)?