Explosions may occur if dry ice is placed in airtight transport containers
BMJ 2001; 322 doi: https://doi.org/10.1136/bmj.322.7283.434/a (Published 17 February 2001) Cite this as: BMJ 2001;322:434
All rapid responses
Rapid responses are electronic comments to the editor. They enable our users to debate issues raised in articles published on bmj.com. A rapid response is first posted online. If you need the URL (web address) of an individual response, simply click on the response headline and copy the URL from the browser window. A proportion of responses will, after editing, be published online and in the print journal as letters, which are indexed in PubMed. Rapid responses are not indexed in PubMed and they are not journal articles. The BMJ reserves the right to remove responses which are being wilfully misrepresented as published articles or when it is brought to our attention that a response spreads misinformation.
From March 2022, the word limit for rapid responses will be 600 words not including references and author details. We will no longer post responses that exceed this limit.
The word limit for letters selected from posted responses remains 300 words.
I am surprised that the danger of carrying dry ice in a closed
thermos bottle is not yet widely known. I learned about it first-hand
thirty years ago when travelling with my wife from New York to Dartmouth
Medical School in Hanover, New Hampshire. I carried a thermos filled with
dry ice into which I had put a tiny vial of frozen bacterial extract. The
cover was screwed on tightly. We boarded a Northeast Airlines commuter
plane, and I set the thermos between us.
Several months earlier, a similar Northeast plane approaching the
local airport had crashed into a nearby mountain, with a number of
fatalities. Our crew was understandably on edge.
Well into the trip there was a Big Bang, and glass fragments
scattered over much of the small cabin. The thermos had disintegrated.
My wife had cuts over her legs and face but stayed quietly in her seat,
bleeding. I was unharmed. Only she and I immediately knew the cause of
the blast.
The shaken stewardess saw that the plane was still flying smoothly,
and then spotted me stretched out on the aisle floor where I was searching
for my precious vial (eventually found intact). When she realized that I
was O.K., she called out to the other passengers to ask if anyone was
hurt. I got up to reassure her: "Nobody," I shouted, "just my wife!".
My wife still reminds me of this on suitable occasions.
Competing interests: No competing interests
I found the excellent article regarding explosions occuring if dry
ice is placed in airtight transport containers disturbing.
The requirements for shipment of dry ice by air is clearly covered in
the IATA Dangerous Goods Regulations (please note that the current edition
is the 42nd!)and in both Packing Instructions 602 and 650. "If carbon
dioxide solid (dry Ice) is used the outer packaging must permit the
release of carbon dioxide gas.
I am aware of an incident a few years ago at one of the boarding
gates at Heathrow. A doctor was taking an infectious sample that was
cooled by dry ice, with him in his carry-on baggage (not permitted under
the regulations). The problem was that the sample and dry ice were in a
thermos flask! This exploded before he boarded the aircraft.
I trust that the requirements of the Packing Instructions 602 and 650
are carefully applied when infectious substances or diagnostic specimens
(as applicable) are being shipped by air (or mail), especially when dry
ice is used outside the watertight secondary packaging to prevent an
explosive situation!
Competing interests: No competing interests
A little knowledge can be dangerous
I read with great interest the letter published in BMJ VOLUME 322, 17
February 2001, from Sally Sharp and colleagues, entitled "Explosions may
occur if dry ice is placed in airtight transport containers".
602 packaging instruction comes by way of the United Nations General
Council, and was designed to ensure the safe transport of infectious
substances carried by air. 602 packaging instructions are based on the
Technical Instructions for the Safe Transport of Dangerous Goods by Air
(Doc 9284-AN/905) adopted by the Council of International Civil Aviation
Organisation (ICAO), and published by ICAO. The International Air
Transport Association (IATA) have adopted, and adapted, these instructions
to produce the IATA Dangerous Goods Regulations. These are published to
provide procedures for the shipper and the operator, by which articles and
substances with hazardous properties can be safely transported by air on
all commercial airlines.
In the UK these packaging requirements (602 or 650) have been
transposed to infectious substances or diagnostic specimens respectively,
carried by road and rail, by the Carriage of Dangerous Goods
(Classification, Packaging and Labelling) and Use of Transportable
Pressure Receptacles Regulations 1996 (the CDGCPL2 Regulations).
IATA Regulations clearly state that for substances shipped
refrigerated or frozen, such as in dry ice, the refrigerant must be placed
outside the secondary container packaging (between the secondary container
carrying the samples, and the outer packaging, usually a fibreboard box).
Interior support must be provided to secure the secondary container in the
original position after the dry ice has dissipated. If dry ice is used as
the refrigerant, the outer packaging must be leak-proof, and allow the
release of carbon dioxide gas.
The secondary container must be leak-proof to prevent the contents
escaping in the event of accident. Thus 602 regulation packaging was never
designed to have dry ice packed in the leak-proof, and hence airtight,
secondary container. Unfortunately, if the packaging regulations are only
known in part, then dry ice inappropriately packed will obviously pose a
serious explosive risk.
Stewart J Gray
PHLS in Wales Group Safety Adviser
No competing interests.
Competing interests: No competing interests