I have some new news and a caution this week about pizza boxes. While there is still some dispute among the public and the paper processers, it turns out that pizza boxes are often considered a minor exception to some of the rules of recycling cardboard.

According to Westrock, one of the world’s largest producers of paper and packaging, pizza boxes are less damaging than we’ve been led to believe. Through a complex study on the amount of grease contained in an average used pizza box, and its impact on the reprocessed paper fibers, WestRock concluded that they should generally have little effect on the paper.

The reason we don’t recycle greasy boxes is that the grease is made up of chemicals that, in sufficient concentration, will interfere with inter-fiber bonding that results in loss of strength in the paper made with those recycled materials. The study looked at several scenarios — topping side up or down, and little to moderate amounts of grease. They found that, on average, pizza boxes contain about 1-2% grease, by weight. That amount can be safely absorbed in the reprocessing and pulping of the used boxes.

Additional food scraps are another matter. Cheese and crusts are definitely not acceptable. My contacts in the local recycling industry assure me that, while they will accept a little grease in the pizza boxes, they cannot accept crumbs, crusts, shards of toppings or glops of old sauce.

One of our local recycling companies says “Once this report was released, we confirmed that as long as there is no actual food (i.e. no pizza crusts or moldy sauce) inside the boxes, we could accept them in our facility to be recycled at the mills, but this is still a grey area for folks at home that we (and others in the industry) are working on.”

So, if the box contains a couple of small spots of grease, it can be recycled. If more than that, or if other food scraps are involved, then the contaminated portion of the box needs to be trashed or composted. Any of the commercial organics recyclers in the Brunswick market can handle those and compost them.

Recycle the pizza boxes, but be very careful to ensure that they are not too contaminated to be safe. Any contaminated portions need to go into your trash, or be put with organics recycling. If contaminated materials go into the blue bins, the entire bin of recycled materials will be trashed by the collection teams. Americans use an estimated 3 billion pizza boxes per year, so a little bit of grease in each can go a very long way. If the privilege is abused, the message from the mills could change, or we could also see the mills refusing to take them at all.

The Recycle Bin is a weekly column on what to recycle, what not to recycle, and why, in Brunswick. The public is encouraged to submit questions by email to brunsrecycleinfo@gmail.com. Harry Hopcroft is a member of the Brunswick Recycling and Sustainability Committee.