The Ministry of the Environment is considering laying charges after the latest emissions flare-up by a Dofasco melt shop that has been the ongoing source of community complaints.

Spokesperson Jennifer Hall said concerns about the release of a massive red cloud by the plant on March 10 have been referred to the ministry's investigations and enforcement branch.

The probe comes little more than a week after residents blasted the ministry's decision to not review the melt shop's operating approvals.

Among the issues in dispute is whether Dofasco - renamed ArcelorMittal Dofasco last fall after its takeover by the European steel-making giant - reported the incident quickly enough.

The company informed the ministry the next day, when a second release reportedly occurred.

"The company is required to report to us and usually it is within a 24-hour cycle, the next day," Ms. Hall said of the March 10 problem.

"They did report it to us, but it didn't happen as quickly as we would have expected," she said.

"We've indicated that the emission trends are concerning and we've gone through our usual process to put this report forward as something that should be further investigated."

Dofasco spokesperson Andrew Sloan said the incident in question occurred when excess molten iron was poured into shallow pits by the plant - a process known as "beaching."

The pits had snow in them and the reaction caused a "sizeable, visible emission."

Mr. Sloan said Dofasco is working to resolve beaching problems, which he attributed to "an unbelievably humid winter with the extra snow."

He said work also continues on $6 million in upgrades to emission controls at the melt shop.

"Nobody wants to see these emissions continue in the state that they have been and as large as they have been," Mr. Sloan said.

"We realize we can't do anything here without the support of our neighbours."

Brenda Johnson, who has worked with neighbouring residents as a project manager with citizens group Environment Hamilton, said she's pleased to see the ministry take some action.

But she said she's also not holding her breath given past disappointments.

"We're happy to hear that the Ministry of the Environment is going to start paying attention," Ms. Johnson said.

"I don't want to say we've gone through this before, but you just treat everything they do as, 'that's just one more step,'" she said.

"You don't get all hyped up because it may not come to be."

The ministry investigation comes only weeks after it denied an Environmental Bill of Rights application filed last July by two neighbouring residents seeking a formal review of the melt shop's operating approvals.

The residents also urged the ministry to force Dofasco to follow through on an apparent commitment in its 2004 annual report to install emission controls to cut the plant's output of heavy metals like lead, chromium, zinc, manganese and copper.

But the ministry rejected the need for a review, citing the steelmaker's ongoing upgrades to existing controls that will continue through next year.

It also said it can't directly monitor the shop's emissions because "technology doesn't presently permit measurements at the stack," so it instead relies on monitoring stations throughout the city.

Mr. Sloan said Dofasco must only report emissions that have 20 per cent opacity and go on for six minutes or more.

"That's one of the issues because sometimes there's emissions that are compliant and those are the guidelines," he said.