Hi Derek

According to WorkSafe https://worksafe.govt.nz/topic-and-industry/dust/silica-dust-in-the-workplace/ or
file:///C:/Users/GJG/Downloads/WKS-17-Dust-silica-dust-in-the-workplace%20(1).pdf

"Use an H-class vacuum cleaner in accordance with
Standard AS/NZS 60335.2.69, fitted with a filter
that can achieve an efficiency of 99.995% (eg H14
HEPA filter complying with Standard AS 4260)."

An M-class vacuum cleaner can have a H14 hepa filter installed but it is still an M-class vacuum cleaner

Hi I have in the past sent copies of SDS to the EPA and asked them to check if they are compliant if I think there is something wrong.
I'm not sure if they follow up on anything.