A large burst of particulate pollution escaped from ArcelorMittal Dofasco Sunday, forming a brown plume over the steelmaker that drifted across some city neighbourhoods.

It's the latest in a series of pollution releases over recent years.

The Ministry of Environment and Climate Change said it takes such events seriously and will meet with the company about the plume this week.

While riding her bike loop on Sunday, Environment Hamilton executive director, Lynda Lukasik noticed the cloud, as something she's far too familiar with, the result of a phenomenon referred to as "coffining."

The east-end resident stopped to take photos and posted them on the Environment Hamilton Facebook page, which has garnered anger and frustration over the steel company's procedure. She has filed a formal complaint with the ministry of Environment and Climate Change.

"We smelled the "stink" of it yesterday while trying to enjoy an otherwise beautiful family oriented weekend & being outside," said one commenter on the group's Facebook page. "I was disgusted and angry we had to endure these foul, toxic, fumes & particulate matter again."

The images capture the burst of pollution that was the result of a process of excess hot metal management — the pouring of liquid iron into slag beds.

According to ArcelorMittal Dofasco manager of corporate affairs, Marie Verdun, there are times when there is more molten iron produced than can be accepted by steelmaking and has to be otherwise dealt with.

The environment ministry said the company reported the "coffining" activities in its daily report to the ministry, and that the ministry received Environment Hamilton's complaint.

"The ministry takes these public concerns very seriously," said ministry spokesperson Lindsay Davidson. "In response to this event, Ministry staff will meet with the company this week to review its existing action plan to reduce the frequency of coffining events and the amount of iron involved, and to determine what further steps may be required."

They need to figure out a way to do this so that they're not impacting on the environment in the way that they do. - Environment Hamilton executive director, Lynda Lukasik

In an email to CBC, Verdun said Sunday's events were cause by a crane failure in their basic oxygen furnace steelmaking stream.

"As a result, the hot metal excess management process had to be implemented very quickly. At the same time, there were significant rains, which made the beds wet and difficult to manage," said Verdun.

Lukasik says the process isn't acceptable and it's been an on-going issue.

"If they know that as soon as there's a down or an issue like this, that they have to turn to this option, then they need to figure out a way to do this so that they're not impacting on the environment in the way that they do," said Lukasik.

She says the environmental group has been tuned into steel industry area emissions for a long time and even has a program called, "stack watch" to encourage people to take note of these occurrences the way they do.

"Our message is that this is not ok. This is not OK in 2017," said Lukasik.

She told CBC that the coffining clouds migrated over her head, into the Hamilton Beach community, causing an off-site impact. "That's cause for concern, where our local environment and the health of our air shed is concerned," said Lukasik.

Verdun says the health risks from the emissions are low.

"The potential health effects from the emissions from excess hot metal management are low as the particulate matter within the excess hot metal management emission is typically a large particle size, which limits the potential for inhalation, and therefore means that there is less potential for an impact to human health..

We do not want to see these kinds of emissions from our operations. - ArcelorMittal Dofasco manager of corporate affairs, Marie Verdun

Lukasik says that ideally the group would love if ArcelorMittal Dofasco operated the plant in balance and had a better system to manage the excess molten iron as well as regulator to require the company to control the emissions.

Lukasik serves on the community liaison committee for the company and has requested they add this topic to the formal agenda for the next meeting at the beginning of November.

"We do not want to see these kinds of emissions from our operations. We do everything in our power to avoid them and we are committed to improving," said Verdun.