Dry ice is a hot commodity because of the vaccine

Massachusetts suppliers are helping to keep Pfizer-BioNTech shipments at minus-94 degrees Fahrenheit.

Fabio De Paula shoveled dry ice into boxes at Acme Ice Company in Cambridge.Jessica Rinaldi/Globe Staff

When the first doses of a COVID-19 vaccine from Pfizer and BioNTech were administered across the United States on Monday, it marked the beginning of a mass distribution effort that hinges on an unlikely product: dry ice.

The Pfizer-BioNTech vaccine needs to be kept at minus-94 degrees Fahrenheit, far beyond the capability of traditional freezers. But dry ice ― which is frozen carbon dioxide ― has a surface temperature of minus-109.3 degrees Fahrenheit, which makes it a sought-after product for shipping and storing the vaccine.

“Our company has been off the wall,” said Marc Savenor, the owner of Acme Ice Company in Cambridge. “At the very beginning of this, I was trying to figure out if we were essential or not, but boy, did I learn quickly that we were essential. The vaccine is being shipped on dry ice.”

Pfizer and BioNTech are distributing doses of the vaccine in custom-made containers, along with an initial supply of dry ice. Some hospitals and other health care centers have access to special ultra-cold freezers to store the vaccine upon arrival. Those that don’t, however, will need to rely on the regular delivery of dry ice to keep the vaccine in the shipping container. Dry ice goes through a process called sublimation, during which it breaks down from a solid into a gas as it is exposed to heat, essentially disappearing instead of melting into a liquid like regular ice.

Charles Ehizuelen placed dry ice on top of a shipment of boxes ready to be delivered to a customer at Acme Dry Ice. Jessica Rinaldi/Globe Staff

“If you contain it, you slow the sublimation rate down, like the Pfizer suitcases do,” Savenor said.

Roughly 10 pounds of dry ice will sublimate every day depending on how it is kept, so the supply needs to be replenished.

“Months ago, who cared about dry ice? Now it is the absolute hottest topic,” said Anna Nagurney, a professor at the University of Massachusetts Amherst who specializes in transportation and logistics. “Some owners of dry ice companies feel they have a moral obligation to assist in preserving the quality of the COVID-19 vaccine.”

Savenor said he’s already fielding orders for dry ice, mostly from hospitals.

“We don’t know how much these people are going to use,” he said. “Until we know exactly how much they are going to need to replenish, we want to be way ahead of the game.”

For Acme Ice, staying ahead of the game means keeping at least 100,000 pounds on hand at all times at the company’s Cambridge headquarters. It also means employees are working around the clock seven days a week, making ice deliveries and fielding phone calls for orders. Most of Acme’s regular dry ice orders go to local biotech laboratories and pharmaceutical companies, but it also delivers to restaurants and bars.

Fabio De Paula pushed an empty container of dry ice out of the way so he could replace it with a full one in order to continue filling orders at Acme Dry Ice. Jessica Rinaldi/Globe Staff

Savenor said the company makes dry ice in a manufacturing plant in Western Massachusetts by liquefying carbon dioxide and compressing it into a solid, frozen form.

At Lake Boone Ice Co. in Hudson, general manager Robert Solomon said many hospitals have already locked in regular shipments of dry ice to ensure they can store and transport the Pfizer-BioNTech vaccine. Even hospitals that have access to ultra-cold freezers are ordering it so they can deliver the vaccine to satellite hospitals or be prepared in case of an emergency, he said.

To keep up with the demand, Solomon said, Lake Boone is ordering 30 to 40 percent more dry ice than usual.

Solomon said the company has been fielding orders for UMass Memorial Health Care in Worcester and Dallas-based Steward Health Care System, which operates hospitals in Massachusetts that include Carney Hospital in Dorchester and St. Elizabeth’s Medical Center in Brighton.

Solomon said he’s been hearing from pharmacies, too, including CVS and Walgreens. Both companies will play a role in the distribution of COVID-19 vaccines to people living and working in long-term care facilities, and eventually they will be at the forefront of providing them to the general public.

A spokesperson for CVS Health said the company’s 10,000 US locations have refrigerator and freezer capacity for several vaccine candidates, including the vaccine from Cambridge-based Moderna, which is expected to receive emergency use authorization as soon as this week. Moderna said its vaccine can be stored at minus-4 degrees Fahrenheit for six months, but it can also be kept in a standard refrigerator for 30 days between 36 and 46 degrees.

For the Pfizer-BioNTech vaccine, CVS said, it will use the special shipping containers for storage, replenishing them with dry ice every five days for 15 days. Once thawed, the vaccine can be be stored in a refrigerator for up to five days.

“My team and I are so proud to be a part of this, and we don’t want to let anyone down,” Acme’s Savenor said.

Nagurney, the UMass professor, said dry ice may also be in high demand for another reason this December: People sending more holiday gifts than usual that require dry ice for shipping, such as perishable food.

“Even I want to send a food basket to a relative,” she said. “I wonder if they will be packing it with dry ice ... It would be bad if there wasn’t enough, but this is a case where you should prioritize [the vaccine].”