It is the legal responsibility of all Canadian employers to ensure their employees are effectively trained.
Where non-compliance is found, inspectors have the power to stop the use of a particular controlled product, which can result in unproductive down time. Penalties for non-compliance include a fine of up to $25,000 and/or a term of up to 12 months in jail.
But more importantly, effective WHMIS training helps increase productivity - online training has been proven to be very effective. WHMIS training also reduces costs related to workplace risk - compensation claims, lost time incidents, insurance fees, clean-up and legal actions.
So the simple answer to 'why do you need WHMIS?' is, because it is the law. But the real answer is that when done well, it is a positive contributor to your workplace culture that will ultimately improve productivity and mitigate risks.
Beware of false certificates!
Neither Health Canada nor any other regulatory authority issues WHMIS certificates. Possession of a third party cerificate does not absolve the employer from their legal responsibility to ensure that employees have been adequately training. Proceed with caution; not all WHMIS training is the same.