Mass Environmental Police use the MSP trunked smartzone system/COMIRS. Here in SE Mass I mostly hear them on TG 39152 (MEP-1) or 2445 (MEP-1) on COMIRS. AFAIK they're dispatched by MEMA State Control. They recently changed they're TG use scheme and I believe there may no longer be a East/West dispatch, both MEP-1 and MEP-3 are patched. MEP-2 and MEP-4 are used for "tactical" comms between units, like when they're doing ORV enforcement operations. I haven't been out west to confirm this though.
There is no "high band" dispatch.