Bio Safety Level 4 – how do they clean/supply?


Watching “The Hot Zone” and the portrayal of the extreme measures required to get into a BSL-4 environment (where extremely hazardous bio-agents like Ebola are kept) led me to wonder, “who the hell cleans up these places?”. What about routine maintenance (changing light bulbs or fixing a leaky faucet) and re-supply? Mopping the floor or changing a light bulb while wearing a biohazard suit can’t be easy.

In: Biology

I don’t know about level 4 contained environments specifically, but I know how the problem is dealt with in operating rooms that have been contaminated and need repair as well as de-con. (ORs don’t really use the Bio Safety Level system, but they would fall between BSL 2 and 3 depending on the patient)

What-ever the repair is (lights, leaky faucet etc) has to wait until the OR has gone through de-con. Then the maintenance person does what they need to do, they clean up their immediate area of work and leave. The room then gets cleaned again before being “open for business”.

For some types of contamination, washing with just hot water and a bactericide is enough. Some places use steam wands (like a pressure sprayer, but the water is hotter than boiling, so it flashes into pressurized steam when it emerges) but certain types of equipment can’t be cleaned that way. There is also a dry ice and alcohol “gun” resembling a sand blasting gun, but using more moderate pressure. You basically sand blast the surfaces with the dry ice/alcohol mix. The result is mechanical abrasion of the microbes, combined with the desiccating effects of alcohol. The draw back is that this needs to be used in well vented areas or separate breathing supply must be provided.

Thus, for a BSL-4, all infectious materials would be removed or locked up in a air tight container. The area would be decontaminated as thoroughly as possible, the staffer would do the work and then the de-con team would sterilize after he leaves. In BSL-4, microbes left by people coming in are as carefully avoided/limited as test microbes escaping. In addition, that maintenance person would almost certainly have the same vaccination and periodic blood work requirements as the researchers.

I don’t know exactly for that level of safety, but there are numerous ways to destroy bacteria/viruses that would make the room safe.

First off, the suits are to prevent humans from being infected. Most bacteria can’t live for very long without a host or energy source (food) so if they make it to a countertop they won’t be alive for long.

If someone needed to access a room like that for maintenance they could use several methods to kill bacteria. They could use UV light, spray it down with chemicals, or fill the room with ethylene oxide gas to sterilize the room. Its unlikely that you can use heat and steam to sterilize in a whole room.