Dry Ice Is Hotter Than Ever

That vaccine, the work of a partnership between Pfizer and BioNTech, is likely to be the first approved by the FDA. It is so delicate that it has to be kept at –70 degrees Celsius (–94 degrees Fahrenheit). That’s not just colder than most freezers; it’s colder than winter at the South Pole. But holding that temperature is not a problem for dry ice, which is a solid at –78 degrees Celsius (–109 degrees Fahrenheit). In fact, for shipping Pfizer’s coronavirus vaccine, nothing else is practical besides dry ice. “There’s really no other way to maintain that temperature stability in transit,” says Azra Behlim, a medical-supply-chain expert at Vizient, a health-care consultancy.

The nation’s dry-ice makers aim to be ready. “We’re getting bombarded with inquiries by hospital districts and public-health departments,” says one employee at a dry-ice supplier, who requested anonymity because he isn’t authorized to speak to the press. Airgas—one of the nation’s largest dry ice companies, with 15 manufacturing sites and 60 distribution centers—is collaborating with the federal government’s vaccine-logistics effort, Operation Warp Speed. “We formed teams to evaluate everything that’s needed throughout the supply chain: How much dry ice might be needed, in different geographies, with different populations. Ensuring the logistics are in place,” says David Joyner, Airgas’s senior director for carbon dioxide. The dry ice planning, says Joyner, is similar to what Airgas did to keep hospitals supplied with medical oxygen during the peak demand in the spring, when the company set up a daily task force to monitor oxygen demand and make sure hospitals got what they needed.

On the other end of the size spectrum are companies like Noble. “We’re currently a one-shift operation,” says Noble’s CEO and owner, Dave Mahoney. “But if the need is there, we can work around the clock if we have to. And if we need to be here around the clock—that’s a good problem to have. It’s just rewarding to know we can be part of the solution to the pandemic.”

Dry ice has long been an indispensable, if mostly invisible, ingredient in the economy. Farmers clean out their wells with it. Cities blast graffiti off walls and statues with it. The nation’s largest meat companies mix it right into their products as they grind them, to keep the temperature safe and the fat from gumming up the grinding equipment. Factories of all kinds—from those that make shoes to those that make frozen waffles—have installed jets of dry ice pellets, right on the manufacturing line, to clean molds in real time.

Dry ice helped remove radioactive debris from helicopters that were used during Japan’s Fukushima Daiichi nuclear disaster in 2011. A company in Utah, Cold Sweep, has perfected using it to lift dirt off the pages and bindings of fragile antique books and manuscripts without harming them. On Broadway, at Halloween parties, and in high-school auditoriums across the country, dry ice makes for convincing theatrical “smoke.”

Dry ice is made by taking purified CO2 gas, chilling it, and pressurizing it to the point that it’s a liquid, then releasing the pressure, which causes the liquid CO2 to take on a snowflake-like consistency. It is then turned into blocks, or into pellets that look like foam shipping peanuts. For cleaning, the dry ice is made into tiny beads the size of rice grains, or smaller. Companies use these like you would use sand-blasting pellets, but once you’ve “dry-ice blasted” a gas turbine, or a mold for making frozen waffles, or the graffiti off a wall, you have no mess to clean up—the dry ice does the cleaning, then simply disappears into the air. Most of the dry ice in the U.S. is made with waste from other kinds of manufacturing—ethanol plants, ammonia and fertilizer factories, and oil refineries produce CO2 as a byproduct, and many capture it to sell to other industrial users. Some of the nation’s biggest dry-ice makers, in fact, colocate their plants adjacent to those facilities, to make using the gas as easy as possible.