Rigid Plastic #6 (Polystyrene) Put in Garbage Cart/Bin Neither foam plastic #6 (expanded polystyrene) or rigid polystyrene are recyclable in San Jose’s curbside program. Did You Know? Plastic in Our Bodies Styrene, a component of polystyrene, has been found in 100 percent of human fat tissue samples dating back to 1986. It is known to cause cancer in animals, and suspected to be both cancerous and a neurotoxin for humans. Find out more from EJnet.org.