Approximately 5,400 smart meters are being replaced across Ontario, due to a risk that they could spark a fire.

The Electrical Safety Authority (ESA) issued a safety bulletin Thursday, explaining that the “Sensus 3.2 with remote disconnect” model of smart meter is susceptible to shorting out.

“These meters can be susceptible to arcing when water or other contaminants get into the meter,” according to the bulletin.

"The probability of a serious safety incident in Ontario is low," said David Collie, ESA's president and CEO. "We're issuing our order as a proactive, preventative step. Even if the risk is low it's better to react now and remove that risk altogether."

This is the latest in concerns about smart meters after the Saskatchewan government ordered SaskPower to remove more than 100,000 newer model meters after it was reported that nine fires were related to the equipment.

The Saskatchewan meters had the similar problems to the ones impacted in Ontario but ESA reports that no local utilities are using the models used in Saskatchewan.

Ontario’s safety alert will impact residences in Oakville, Sarnia, Waterloo, Kitchener and Sudbury, but will not impact Hydro One and Toronto Hydro customers. It is reported that the bulk of people impacted are from the Sarnia region.

According to the ESA, the 5,400 affected meters comprise less than one per cent of the 4.8 million meters installed across Ontario.

The ESA has asked local utilities to contact customers impacted by the bulletin with a deadline to remove them set for March 31. Members are also being urged by the ESA to not attempt to remove or alter the meters themselves.

The bulletin comes on the heels of a firestorm of criticism last month, when auditor general Bonnie Lysyk criticized the effectiveness of the $2-billion smart meter program , which is double its projected cost.

Lysyk claimed that the meters have not led to the government’s electricity conservation goals being met.

Meanwhile, NDP’s Peter Tabuns said that his party raised the issue last summer. But he said his party was told by the energy minister that the Saskatchewan meters were not in Ontario.

"(They said) don't worry, be happy, go home," Tabuns said. "Happily the ESA actually looked at the problem, realized it wasn't just one make of meter, that it was a larger problem and they're taking action. The government should have recognized last August that it couldn't just dismiss the problem."

Ontario environmental commissioner Gord Miller also had concerns about the meters when he said that the gap between peak and off-peak prices needs to be a lot higher in order to encourage people to conserve.

With files from CTV Toronto's Paul Bliss and The Canadian Press