Petro-Canada was charged with “discharging a contaminant into the environment”, an offence under the Ontario Environmental Protection Act. In fact, a pipe had failed and leaked gasoline but Petro-Canada responded quickly. It was also established that there were a number of safety systems and procedures in place. Petro-Canada claimed due diligence as a defence. Explain what must be established to succeed in a due diligence defence and on which side the onus of proof resides. How would it affect your deliberations to know they had used piping “not up to industry standards”?