That would make a great sci-fi thriller, if it doesn't already exist:)

That happens in The Andromeda Strain, but they don't really explore the implications.

Mutant 59: The Plastic Eater

Not too bad for a 70s book. There's also "Directive 51"

This is what I'm afraid of - it's all great when the fungus is only in a landfill or the ocean but what happens if it gets inside my car ? Etc etc