Styrofoam toxicity

[woodenfish]

It is a type of polystyrene

In a couple of threads, the styrofoam is actually a permanent part that is immersed in the tank. A few coats of colored cement are put on it.

The thread even called for using a hot gun to round off sharp edges after carving the stacked styrofoam.

I use styrofoam in aquascaping but only as a mold to make rock. As I use a hot gun on it, a smell emits, the same odor as in ironing permanent press shirts.

Is the permanent immersion of styrofoam OK, particularily after a hot gun was used to round off sharp edges?

Does it have to rely on the layers of cement sealing off the styrofoam. I found this hard to accept, as cement is porous to some degree, even very specialized cement, IMO.

I will dig out the threads if needed.

I must say I am impressed with the looks of this approach, but is it safe?

[brewmaster15]

A few years ago I would have said that Polystyrene was safe in a tank as it virtually did not decompose...a styro cup for example would be in a landfill archeological dig thousands and thousands of years from now, completely undegraded...

Now though..many manufacturers are producing stryo that does break down...and some does so rapidly...so I guess it really depends on the particular styro.

Sorry if that doesn't help,
al