The Ford government is boosting the province's powers to slap fines on industry for breaking Ontario's environmental rules, but environmental activists say there's an important catch that actually weakens protections against air pollution.

This month, changes took effect giving provincial environmental officers wider scope to issue fines for such violations as emitting excess sulphur dioxide, a toxic compound typically released by oil refineries. The maximum fine is now $200,000, double the previous limit.

The government pitches this as part of Premier Doug Ford`s promise to "come down heavy" on polluters.

However, an environmental watchdog group says the increase in fines is outweighed by a separate move that allows refineries to pollute more.

Last fall, the province quietly changed a regulation under Ontario's Environmental Protection Act to exempt sulphur dioxide "flaring" incidents at petroleum refineries from meeting the province's air quality standards.

Premier Doug Ford has promised to 'come down heavy' on polluters as part of his government's environmental policies. (Nathan Denette/The Canadian Press)

Flaring incidents — in which refineries burn off excess crude oil products that cannot be processed — emit large quantities of sulphur dioxide in a short period of time. The flaring rules had been tightened by the previous Liberal government in March 2018.

"My guess is heavy industry lobbying, that they didn't like the changes that had been made to the law just before the last government left," said Elaine MacDonald, healthy communities director for Ecojustice, a Toronto-based environmental law charity.

Sulphur dioxide (SO2) emissions are a "serious health concern," said MacDonald, especially for people with respiratory problems such as asthma. She said flaring incidents can cause acute breathing problems for people nearby

"The reality is right now there's no air quality standard that applies to the flaring of acid gas at refineries," said MacDonald in an interview.

"So communities are vulnerable to spikes and high concentrations of sulphur dioxide from facilities flaring acid gas. And there's no enforcement that can be done to prevent that from occurring, because they've just exempted that completely."

Distilling towers rise above the Suncor oil refinery in Sarnia, Ont. (Carlos Osorio/AP)

Imperial Oil owns the two largest refineries in Ontario, at Sarnia and Nanticoke. Two others in Sarnia are owned by Suncor and Shell.

"Flaring is an important safety measure and environmental control tool that keeps our facilities running safely," says a statement on the Imperial Oil website. "In recent years, Imperial has taken steps to recover and reprocess excess materials to lessen the flaring on a day-to-day basis."

A large flaring incident at Imperial`s Sarnia refinery in 2017 triggered an investigation, but the government announced this past March that no charges would be laid.

Environment Minister Jeff Yurek was not available for an interview this week.

In a statement emailed to CBC News, Yurek's press secretary Andrew Buttigieg said the enhanced fines "provide incentive to facilities to make operational improvements that can reduce the incidents of sulphur dioxide flaring and improve environmental protection."

Videos shared on social media showed towering flames burning at the Imperial Oil refinery in Sarnia. Ont. in February 2017. Ontario's environment ministry chose not to lay charges as a result of the flaring incident. (Lisa Pugliano Mrowiec/Facebook)

The rule changes that came into effect July 1 require facilities to report emissions after each flaring incident. The government "may issue an environmental penalty," said Buttigieg, if more than 225 kilograms of sulphur dioxide is discharged in a 24-hour period.

He said the government is "setting clear rules so good actors can get on with business while also ensuring we have strong enforcement for those who don't obey the rules."

MacDonald argues that penalties fail to stop excessive sulphur dioxide emissions from happening. "You're collecting money after the fact, but you're not preventing a dangerous air quality level," she said.

The Ford government should eliminate the exemption for flaring, said MacDonald. She says that would mean refineries only get approval to operate if they can limit their sulphur dioxide emissions during flaring to the provincial air quality standards.

CBC News contacted an Imperial Oil spokesperson on Friday. She said she did not have "anything to add" about the changes.