Enbridge Gas is notifying customers of a data security incident that occurred about seven months ago.
Spokesperson Natasha Carr confirmed the breach involved one of the company's third-party vendors.
"This breach has compromised some information from select commercial, industrial and residential customers," said Carr. "However, no personal information has been compromised."
In a letter sent to customers, Marketing and Energy Conservation Director Sarah Van Der Paelt said names, service addresses, and account numbers were compromised in the breach on or around May 31.
Van Der Paelt said the full extent of the data security breach at CLEAResult was not communicated to Enbridge until November 16.
"We are treating this situation very seriously and taking steps to mitigate potential risks to customers impacted by this data breach, including communications with affected customers and additional internal monitoring of accounts," said Van Der Paelt.
She encouraged customers to remain vigilant by reviewing their account information online.
"Using My Account, [confirm] your contact, address and other information has not changed," Van Der Paelt said. "For those customers who do not currently have an Enbridge Gas online My Account profile, please create one. Creating an online account and password offers additional security protections and will prevent others from being able to create an account on your behalf."
Van Der Paelt said the company regrets any concern the situation has caused its customers.