On Friday, October 9, 2015 at 9:54:42 AM UTC-4, Ignoramus17325 wrote:

I do not see how a certificate could prevent what happened.

A certificate, of course, would not prevent such an accident. It would, however, satisfy the authorities and the insurance companies that you, as an employer, took reasonable measures (by getting your employees certified) to avoid the incident.

Just as you wouldn't send an unlicensed driver out in your company truck it would be foolish to invite wrath from above to save $38.