OSHA Fit Test Program - FACE MASKS
Having an established "Fit Test Program" for your employees is an OSHA mandate and not just friendly advice.
Failure to meet OSHA standards can rack up to $10,000 in fines per occurrence.
Here is a link for OSHA. Print this out and keep it in your MSDS binder in the trailer and in the office were you store chemicals. Maintaining MSDS sheets is also an OSHA requirement.