Stephen Petty - On the effectiveness of masks

Stephen Petty is a Certified Industrial Hygienist (C.I.H.), Certified Safety Professional (C.S.P.), and Professional Engineer (P.E.).

He has been a testifying expert in nearly 400 cases on exposure, exposure control, PPE and warnings and has completed or supervised thousands of forensics projects mostly for the insurance industry.

He explains to a committee panel why masks don't work.