NIH is about 10 minutes down the road from me. Unless they’ve made some changes in the last four years it’s a small Level 4 lab that they’ve been operating under Level 3 protocols. There’s a big difference. Unless they’ve been operating and testing the air handling units on a regular basis they might not have the Level 4 protection they think they have. Seals and belts need maintenance.
NIH recent history on storage and handling of lethal biologicals is not confidence inspiring.