[sudosysgen]

> tripletao 2 minutes ago | parent | context | flag | on: Scientists believed Covid leaked from Wuhan lab, b...

Beyond that, the original SARS escaped at least once from a BSL-4 lab in Taiwan:

> The scientist had been working on a SARS study in Taiwan's only biosafety level 4 lab since June, the Taiwan statement said. [...] A chest x-ray showed pneumonia in his right lung, and polymerase chain reaction tests of throat and blood samples were positive for the SARS virus.

Many viruses have come to infect people in BSL4 labs, when they happen to be run incompetently.

From the exact same article you cite :

> The AP report quoted Dr. Shigeru Omi, the WHO's Western Pacific regional director, as saying the patient most likely was infected by some spilled liquid he saw on the surface of a test tube. Omi said the man was working without protective gear, such as a gown and gloves, at the time, according to the report.

Which, again, does nothing to oppose the thesis in the original post, which is that these viruses won't escape a BSL4 lab that's actually operating competently at the BSL4 level.

> The idea that "BSL-4" implies "negligible risk of accident" seems to be empirically false. In any case, the WIV was creating chimeras of novel coronaviruses with much looser precautions, at BSL-2:

That was also explicitely addressed. In 2013, the WIV was not a BSL4 lab.

[tripletao]

A BSL-4 lab operated by researchers who never made mistakes would probably be quite safe. Unfortunately, they're instead operated by flawed humans. If you look at the safety culture of nuclear engineering, aviation, or other fundamentally dangerous activities that we nonetheless manage to practice safely, then you'll see practitioners who recognize that. They don't dismiss accidents or near-accidents as human error, even if a human failed to follow a procedure, and instead look for better ways to build systems tolerant of the human errors that inevitably occur. The attitude I've seen from many virologists--or at least, from the virologists with the perhaps-questionable judgment required to become the public face of these arguments--is disturbingly different.

And yeah, the WIV was working with novel bat-origin coronaviruses at BSL-2, not 4. That makes the risk of an accident yet higher, which makes our reddit virologist's argument that "BSL-4 labs like the WIV are really safe" not just bad but also dishonest. So I'm not sure what you think is addressed?

ETA: And I see that the reddit post talks about the WIV doing work at BSL-3 before they opened their BSL-4 lab. This claim is unreferenced, and as far as I can tell it's false; Dr. Shi confirms that they were working at BSL-2:

> In an email, Zhengli Shi said she followed Chinese rules that are similar to those in the US. Safety requirements are based on what virus you are studying. Since bat viruses like WIV1 haven’t been confirmed to cause disease in human beings, her biosafety committee recommended BSL-2 for engineering them and testing them and BSL-3 for any animal experiments.

The reddit post could easily be read to imply that after the BSL-4 lab opened, all work moved to the higher BSL; but it never actually says that, and I'm not aware of any evidence (or even any claim from the WIV) that it did. There's a strong incentive to work at lower BSL even when a higher-level facility is available, since the extra precautions significantly slow work. I therefore believe it's likely that work was continuing at BSL-2 in 2019.