In the U.S., about 700 million pallets are produced and recycled each year.
Around 4 billion wooden and plastic pallets are currently in use.
Nearly 40 percent of all hardwood produced in the U.S. goes into pallet production.
Penn State researchers wanted to know if wood or plastic pallets were better for the environment, so they studied pallets from cradle-to-grave.
The study looked at nine different factors, from ozone layer depletion and ecotoxicity, to global warming and non-renewable energy.
They found that wooden pallets are more environmentally friendly than plastic pallets.
Molded plastic pallets last longer, but are derived from petroleum or natural gas products, which greatly increases their carbon footprint.
They also found that conventional and RF heat treatment for wooden pallets is more sustainable than methyl bromide fumigation treatment.