New requirements for use and storage of liquid nitrogen, dry ice

Laboratories using LN2 minimally may have one or two tanks stored in a closet space with little ventilation, Dr. Branton says. “But that is a tragedy waiting to happen, because even a small leak will displace a large amount of oxygen quickly.”

The asphyxiation risk extends to dry ice, which can displace oxygen with CO₂. Says Dr. Mayer: “There have been cases where lab workers bend over into chest freezers used to store dry ice. They put their heads into the freezer chambers to find something, and if the oxygen has been replaced by CO₂, they quickly pass out. They don’t even realize anything is happening to them; it is like going to sleep. They are found later—dead, hanging over the freezer.”

All laboratories must know that proper ventilation and high turnover of air in storage and usage areas are imperative, he adds.
Other additions to the requirement call for “training on the safe handling of LN2 and dry ice” and signs marking areas where LN2 and dry ice are used and stored. “The training referenced in the note alerts labs to provide training specific to LN2 and dry ice,” Dr. West says. “We wanted to bring attention to the need to understand certain things about safe use of LN2, including storage tanks,” for example.

Dr. Branton says he has seen LN2 stored in tanks “the size of soda bottles” as well as in large tanks weighing 200 pounds. “Left unrestrained, they can tip over and result in serious crush injuries. It’s one of the odd little things people don’t usually stop to think about.”

GEN.77550 “Liquid Nitrogen Environmental Monitoring” is a new requirement calling for oxygen sensors with a low-oxygen alarm mounted in an appropriate location and sufficient airflow to prevent asphyxiation in areas where liquid nitrogen is used. Appropriate placement of sensors is at typical breathing height, it says. This requirement is in the biorepository checklist as GEN.84800.

“I have inspected storage areas in some labs that are a closet in the basement,” Dr. Branton says, “with a monitor up at the ceiling. First, there should be several monitors installed, in the event there is a pocket of gas caused by air currents in one part of the room. And they must be installed at human levels.”

Because LN2 is a heavy gas, it falls to the floor first and fills the room from floor to ceiling. “If an alarm is six to eight feet above the floor, the entire room would have to fill with nitrogen before the alarm goes off,” he says. “If a lab worker were seated on the floor or on a low stool, the alarm would be too late for them. They could be passed out or dead by the time it sounded. Sensors must be at the height you are working, more likely waist
level than eye level.”

Also for the safety of personnel, there is a new requirement calling for a written policy for restricting access to the laboratory to authorized individuals.
“There are many compelling reasons to require controlled access,” Dr. West says of GEN.59980 “Restricted Laboratory Access.”

“We deal with patients all the time in our facilities, and that creates patient privacy issues when they are giving specimens or having blood drawn. There are patient specimens in our facilities. There is a lot of private data in various locations and various forms within the lab that need to be protected from a HIPAA perspective.” And there are visitors—people coming from different parts of the hospital to drop things off, for example. “You wouldn’t want nurses from the floor walking into the wrong section of the microbiology laboratory while lab workers are dealing with culture and specimens,” Dr. West says. Some transfusion medicine laboratories use cesium irradiators, which require restricted access.

“Lastly, unfortunately there is a need for protection against malicious events,” Dr. West says. “Whether someone intends physical harm to employees and/or patients, or just destruction to lab equipment, supplies, and/or records, we must take steps to safeguard against such possibilities.”

Until now, there was no requirement for laboratories to have a specific policy for access. “When the Checklists Committee tackled this, we took into account the variety of labs we serve, from highly complex, large labs with hundreds to a thousand employees, all the way to rural settings where a small group of individuals provide laboratory services,” Dr. West explains. “There is a huge spectrum, so we did not believe there was a way for us as a committee to prescribe to them exactly how to do this in a universal way. We decided to say, ‘You need to sit down in your own laboratory environment and contemplate these issues and come up with a policy and procedure to decide what kind of control to access is needed in your lab and which authorized individuals will be allowed.’”

Inspectors will ask to see the policy and procedures. “They will want to see what the lab thought about, what they decided, and how they will carry it out. While we do not prescribe what labs can and cannot do,” Dr. West says, “we want them to think about systems for handling different situations.”

In the discussions of safety now covered in the 2018 checklists, other important issues were raised. Drs. Branton and Mayer pointed to a need to safeguard specimens that are stored frozen by way of LN2 and dry ice and in electrical freezers. The imperatives to ensure specimen safety, to maintain adequate backup tanks and freezers in the event a freezing unit becomes inactivated, and to consider these specimens in times of disaster have all been brought to the table. “We are looking at these things for 2019,” Dr. West says. 

Valerie Neff Newitt is a writer in Audubon, Pa.

The CAP Council on Accreditation leads the work to reexamine and revise the checklists. For some of the other revisions found in the 2018 edition, see the August and September 2018 issues of CAP TODAY.