Biohazard levels discussion
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Date: Sat, 30 Jan 1999 18:15:48 -0500 (EST)
From: The Man in Black

We should all be familiar with Biohazard Levels 1-4, but what about the theoretical levels of five, six and seven?

BIOHAZARD LEVEL FIVE would be engineered biowarfare agents or Binary compounds in close proximity.

BIOHAZARD LEVEL SIX would be newly engineered experimental agents or unknown agents.

BIOHAZARD LEVEL SEVEN would be xenobiological, extraterrestrial, or alien biological agents, whether used for biowarfare or not.

Date: Mon, 1 Feb 1999 00:21:57 +0900 (JST)
From: Jay and Mikiko

Actually, I'm not. I could guess, but if anyone knows exactly how they break down, I'd love to hear it.

Date: Sun, 31 Jan 1999 11:46:07 -0500 (EST)
From: John Petherick

Actually, I'm not. I could guess, but if anyone knows exactly how

From the CDC page on Biosafety in Microbiological and Biological Laboratories at , in Section 3

The definitions of L-1 to L-4 are:

Biosafety Level 1:

- work involving well-characterized agents not known to cause disease in healthy adult humans, and of minimal potential hazard to laboratory personnel and the environment

- no special precautions beyond what you learned in college microbiology lab

- in other words, your college microbiology laboratory

- examples include known organisms not listed as requiring a higher BSL

Biosafety Level 2:

- work involving agents of moderate potential hazard to personnel and the environment.

- restricted access, training on the hazard(s) of the infectious agents, sterilization of waste, standard "sharps" handling, PPE required, etc.

- immunization, if available

- in other words, the standard diagnostic medical laboratory

- example organisms: infectious stages of Plasmodium sp. (malaria), most activities using Chlamydia, work using Mycobacterium leprae (Hansen's Disease), Treponema pallidum (syphilis), Hepatitis A, human herpesviruses, contemporary strains of influenza, poxviruses (including smallpox), dengue

Biosafety Level 3:

- clinical, diagnostic, teaching, research, or production facilities in which work is done with indigenous or exotic agents which may cause serious or potentially lethal disease as a result of exposure by the inhalation route

- as above, plus higher level of training and supervision, biological safety cabinets, a two-door airlock system, immunization

- vaccine production, research labs, referral medical diagnostic laboratories

- example organisms or procedures: Histoplasma capsulatum contaminated soil (histoplasmosis), production of Baccilus anthraci (anthrax), production of Clostridium botulinum (botulism), production of Yersinia pestis (plague), historical or recombinant strains of influenza, production of rabies, production quantities of HIV or SIV

Biosafety Level 4:

- work with dangerous and exotic agents which pose a high individual risk of aerosol-transmitted laboratory infections and life-threatening disease. Agents with a close or identical antigenic relationship to Biosafety Level 4 agents are handled at this level until sufficient data are obtained either to confirm continued work at this level, or to work with them at a lower level.

- the whole nine yards, like "Hot Zone"

- examples include: Ebola, Marburg, Lassa

Note that there are some some crossovers. For example, diagnostics work on HIV specimens should be done in a BSL-2 facility using BSL-3 equipment and procedures. For many agents, diagnostic work is BSL-2 while production is BSL-3. While all research work involving pox viruses is BSL-2 work, the only facility known to have a sample of smallpox is the CDC.

There's a companion document for animal biosafety practices (ABSL) where handling and confinement for infected animals is described. I couldn't find anything about clinical isolation fo human patients, but general procedures would be similar to those for research animals.

Date: Sun, 31 Jan 1999 12:42:35 -0500
From: Graeme Price

John bet me to the punchline when he wrote:

Biosafety Level 2: contemporary strains of influenza, poxviruses (including smallpox),

NO! Not including smallpox… you can handle poxviruses safely at level 2, but only if you are vaccinated. In fact, all work on Smallpox (such as it is now) is done under very close supervison at one of the two labs (see below) that actually still have it… I think they may mean "smallpox vaccine" here.

Note that there are some some crossovers. For example, diagnostics work on HIV specimens should be done in a BSL-2 facility using BSL-3 equipment and procedures. For many agents, diagnostic work is BSL-2 while production is BSL-3. While all research work involving pox viruses is BSL-2 work, the only facility known to have a sample of smallpox is the CDC.

Very true. In fact, most BSL-3 agents can be (read are) handled at BSL-2 conditions in diagnostic labs, provided they are in small quantities (things like small volumes of blood from HIV patients)… larger volumes require BSL-3 conditions. Also there are 2 facilites with Smallpox: The CDC and the VECTOR research facility in Russia. This has all been discussed before though and should be in the archives.

The words "Trexler portable isolator" leap to mind here. This is basically a plastic tent with built in gloves and airlock that can be erected around a conventional hospital bed. Not sure how may hopsitals still have this stuff though. Certainly in the 1960's there was a lot of worry about moving Lassa patients around - some medical personnel were actually evacuated from outbreak sites to Germany in an Apollo (or possibly Gemini, I forget) space capsule on loan from NASA. In other words, try not to get infected with a BSL-4 agent. Thank you.

Date: Sun, 31 Jan 1999 12:28:28 -0500
From: Graeme Price

Jay wrote:

Actually, I'm not. I could guess, but if anyone knows exactly how they break down, I'd love to hear it.

One for me, I fear. The laboratory (and production facility/animal room) biohazard classifications (in the US known as BSL 1-4 [BSL for Biological Safety Level], in the UK as P 1-4 [P for pathogen] or sometimes as category 1-4) run something like this (I've used one of my safety manuals to get the fine points).

Level 0: No risk whatsoever. No micro organisms handled or stored here. Effectively "clean". No protective apparatus or procedures required. This would be something like the coffee room, or an office.

Level 1: Most laboratories fit into this band. Minimal risk of infection to healthy individuals. Organisms handled here would be non-pathogenic for humans (things like lab strains of E.coli or yeast which have been crippled for genetic engineering purposes). Laboratory coats required, no eating and drinking, no application of cosmetics (yes, really), good laboratory practices to be followed.

Level 2: This would be most clinical labs, and most microbiology labs. Organisms handled here may cause human disease and may be a hazard to laboratory workers, but are unlikely to spread in the community. Lab exposure rarely produces infection and effective prophylaxix (vaccination) or treatment is usually available. This would include things like influenza virus, Salmonella, Streptococci etc. All Level 1 precautions must be followed, plus hand washing facilities must be provided (in the US - this is mandatory for Level 1 in the UK), access to the laboratory must be restricted to authorised personnel, room must be under negative pressure if air-conditioned, all waste materials must be sterilised by autoclaving prior to final disposal. I routinely work under Level 2 conditions. It's pretty straightforward, actually.

Level 3: Starting to get more nasty here. This is what would routinely be called a "containment lab". Level 3 organisms may cause severe human disease and present a serious hazard to laboratory workers. They may present a risk of spread in the community but there is usually effective prophylaxis or treatment available. This includes things like Mycobacterium tuberculosis, HIV, Hepatitis B, Yellow Fever and CJD (the latter due to the uncertain risk involved in handling it). All Level 1 and 2 precautions apply, plus gloves may be required at all times (depending on what you are using), splash-proof overgowns may be worn over lab coats, safety cabinets must be used at all times when handling organisms, there should be an autoclave en suite, all materials should be decontaminated before removal, the room is maintained under negative pressure at all times with air vented to the outside via a HEPA (high efficiency particulate air) filter and door must be kept close whilst work is in progress. I have worked under these conditions. It's less fun and more awkward generally.

Level 4: EEEK! This is the really dodgy stuff. Level 4 organisms cause severe human disease and are a serious hazard to laboratory workers. They may present a high risk of spread in the community and there is usually no effective prophylaxis or treatment. This is things like Ebola, Marburg, Hanta virus, the Argentine and Bolivian haemorrhagic fever viruses etc. All Level 1, 2 and 3 conditions apply, plus…. shower on the way and out, rooms under negative pressure, lab must be in a seperate part of the building (preferably in a seperate building) restricted to authorised personnel and there must be a key procedure to restrict entry at all times. Entry is though an airlock, with the clean side of the airlock operated from the restricted side by changing and showering facilities and preferably by interlocking doors. The outer door must be labelled with a "work in progress" sign. Then there are about another 3 pages of regulations which concern airflow and emergency procedures (nothing very exciting though). In the US there is a tendency to require fully enclosed "space suits" working from an external air supply in Level 4 labs. In the UK, this is regarded as a bit extreme and all work is done inside glove boxes (also sometimes called "Porton Cabinets" for obvious reasons) which are sealed from the environment. The Russians seem to take this to extremes and use gloveboxes whilst wearing full suits. Perhaps they know something we don't.

Anyway, I hear rumours (currently unconfimed…. and they came from our Biosafety officer, who isn't 100% reliable) that there is a "Level 5" containment classification. Personally I think she is talking rubbish, unless Level 4 has been split up, with use of gloveboxes now at Level 4 and the use of suits at Level 5. I will try and look this up. Note that most large animal work (particularly with infected monkeys) using Level 4 organisms will require the use of suits, although you could probably use mice in a Porton Cabinet.

Anyway, this ought to explain things a bit better.

Date: Mon, 1 Feb 1999 09:17:02 -0800 (PST)
From: Doug Iannelli

I'm brand new to this forum, so excuse any lack of decorum. First, a little background:

Regarding the Biohazard Levels, as far as I was aware, Levels 1-4 were the only ones in use by USAMRIID at the time of my service. This however, is obviously subject to change. I will be attending a school on Weapons of Mass Destruction (WMD) for AFD in the near future and will let you know if I find out otherwise. This course should cover the area as it deals with nuclear, biological and chemical threats. Although I have to admit, I don't see the use in training municipal firefighters in dealing with these types of incidents. Even in a HazMat incident involving federal, military, or terrorist materials, the feds have jurisdiction and we are to assume a "stand clear" policy and allow them to mop it up.

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