Pollution caused by styrofoam used in docks
 

Is it legal to use styrofoam flotation on swim platforms and floating docks? The styrofoam degrades over time and also is brrowed into by animals causing the degredation of the foam breaking pieces free polluting the lake and washing up on shore.

can not say i know enough to answer Blue...but sounds like there are better options based on the issues you presented...

Marinas and gas docks have since discontinued the use of "Styrofoam" material for flotation. Gasoline and oil film on the water surface eventually dissolves the Styrofoam at the waterline and periodically has to be replaced. Floating docks are now supported by hollow plastic, and sometimes cast concrete tubs which last much longer and are easier to clean. Styrofoam has very little strength and had to be "boxed" in/confined. :) NB

I don't know if the kind you are talking about without the polyethylene shell is illegal but the experience I have has with our floating docks is good. They are constructed with Rugged polyethylene flotation with foam core and have a life time guarantee. The foam is close celled. We are very pleased with the construction.
Most floating drive on docks you buy for PWC or boats are the same, with a few exceptions.
The foam flotation without the polyethylene, you are talking about, does breakdown and go everywhere I would not recommend it to anyone.

If it wasn't legal it wouldn't still be used.

In general, although not "illegal" in the sense of the word, styrofoam floatation that is "pelletized" styrofoam is not being used anymore. The typical styrofoam being used now for floatation is the closed cell type.

Right up my alley
 

I happen to be looking at our styro production plant as I write this.We manufacture EPS(expanded poystryrene) which is what BT is refering to.White bead styro like that which is used in Styro coolers and different packaging.It should never be used for flotation in a "raw" state.It degrades pretty quickly from uv and it will always continue to flake off.Most stryo that is used for flotation is extruded polystyrene(closed cell) which stands up much better.These buns are usually pink or blue.

NB,we sell to big marinas that do use our EPS but concrete is cast around it.And as Aqua pointed out it can have a rigid PE exterior also.But in his case I think that they are filled with an expanding spray foam like urethane.

It may be closed cell poly that I have been seeing floating in the water and washing up on beaches. I talked to several people that said that animals like to borrow into it and make nice homes inside them in the off season

Even with me being an owner of an EPS plant,I've always been against using it alone as flotation for this reason.