Polystyrene foam (also known as Styrofoam) emits harmful and carcinogenic compounds into the environment and into the food it carries.

The following information is from the National Toxicology Program's Report on Carcinogens, Twelfth Edition (2011):

"Styrene is reasonably anticipated to be a human carcinogen based on limited evidence of carcinogenicity from studies in humans, sufficient evidence of carcinogenicity from studies in experimental animals, and supporting data on mechanisms of carcinogenesis.
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The presence of styrene in packaged foods is due primarily to leaching of monomer from polystyrene containers (Howard 1989, ATSDR 2010). "

Polystyrene also has severe environmental impact as it takes several centuries to degrade, and it poisons the birds who eat it during this time.

Jamba Juice is already using paper cups in cities that have banned the use of polystyrene foam. There would be a great benefit to the environment and to public health if Jamba Juice stopped using polystyrene foam cups entirely.