An Ontario MP is calling on a regional councillor to resign after the councillor sent out a pornographic image in a reply-all email about a road closure.

Chris Bittle, Liberal MP for St. Catharines, says Coun. Andy Petrowski's email containing a picture of naked woman with her legs spread is just the latest in an egregious list of acts that includes "homophobic, Islamaphobic [and] racist" remarks on Twitter.

"This is so unusual, so bizarre, that I have to get involved," Bittle told CBC News.

Petrowski sent the image to dozens of people on Monday. Four minutes later, he emailed again saying both that it was supposed to be a private message, and that someone else had been using his iPad.

It's probably time for Andy to consider resignation. - Tony Quirk, regional councillor for Grimsby

Petrowski did not immediately respond to requests for comment from CBC News.

It started when a regional staffer emailed about work on St. Paul Street West over the Burgoyne Bridge, which is a contentious nearly $100-million project in the region. Bruce Timms, a St. Catharines regional councillor, replied that it will be good to see final touches made on the bridge.

Petrowski replied to 95 recipients, including the fire chief, Horizon Utilities and Niagara Student Transportation Services.

"There must have been a sale on these multi-million dollar, taxpayer-funded, non-functional arches ... guess who put these up in Ottawa?" he wrote. "You're right if you said .... drum roll, please....'Pomerlau'...what a joke!"

He attached a photo of a nude woman sitting in a chair with her legs spread.

Petrowski followed up in a second email four minutes later, saying, "I apologize to everyone for the previous e-mail just sent … this was sent in error as a terrible message by someone who was using my iPad I thought to send a private message. I am very sorry for this unacceptable and inappropriate transmission."

Bittle, who has called for Petrowksi's resignation before, says this is more evidence that he's unfit for office.

"This pattern has continued without any contrition, without any change," he said. "It's time for him to resign."

Tony Quirk, regional councillor for Grimsby, said the region issues iPads for council use. Petrowski appears to have inappropriate images stored on his, he said.

"It's probably time for Andy to consider resignation."

Comments about Muslims and same-sex marriage

Alan Caslin, regional chair, said he plans to meet with Petrowski Tuesday to discuss "limits on his regional devices and email accounts." He's also asking Petrowski, the subject of recent integrity commissioner investigations, to resign.

Petrowski has been a divisive figure in Niagara politics for years.

In 2015, he tweeted that Barack Obama had a "perverted mind" for condoning same-sex marriages on the same day he sang Amazing Grace, the St. Catharines Standard reported. He later apologized.

There were also calls for him to resign as vice-chair of the police services board that year when he made comments about Syrian refugees and a proposal by then-U.S. presidential hopeful Donald Trump to ban Muslims from entering the United States.

Petrowski said a refugee could enter the Eaton Centre with a machine gun in his or her hands and "wipe people out," The St. Catharines Standard reported.

Petrowski later stepped down, saying he wanted to spend time with his elderly father.

'Third or fourth last straw'

More recently, he threatened to sue fellow councillors.

On Twitter, Petrowski describes himself as "Pro-Trump, Pro-Nationalism, Pro-Life, Pro-Jesus, Pro-Constitution, Pro-Speech, Anti-LEFT, Climate Change is Natural. #MAGA."

​Dave Augustyn, the mayor of Pelham, Ont., and a regional councillor, called it "the third or fourth last straw with this particular councillor."

"The behaviour of this councillor continues to be a huge distraction and keeps us from really concentrating on the other work we're supposed to be doing," he said.

MP Chris Bittle issued this statement, above, on Monday afternoon.

samantha.craggs@cbc.ca | @SamCraggsCBC