The cleanup is underway after a massive oil spill in the Peace Country. Residents in the community of Little Buffalo wonder what this leak could mean for them in the long-term.

The leak happened last Friday in the community located about 100 kilometres northeast of Peace River. The Energy Resources Conservation Board (ERCB) say the pipeline was sealed the same day it ruptured, but not before the 28,000 barrels of crude poured out.

Residents now have concerns about breathing the air.

"Very worried...I still have a headaches, it comes and goes," one resident told CTV News.

People in the community are worried about the long-term health effects from the leak.

"This is the biggest oil spill since 1975 and this is happening next door to a community," said Melina Laboucan-Massimo, whose family lives near the spill site.

The pipeline was built in 1966 and runs more than 700 kilometres from the Peace River region to Edmonton.

The cause of the spill is still unknown.

Resident Veronica Okemow doesn't know what to tell her children. The local school remains closed after reports of nausea and disorientation.

The ERCB insists there are no airborne environmental concerns and that any odour, is not coming from the spill.

"There is a significant odour there, but we're not sure what it is...our staff is confident it is not a result of this leak," said Davis Sheremata with the ERCB.

The environment minister is expressing disappointment and uncertainty for the company involved.

"It's too early to speculate whether charges would come into play...clearly the charges would relate to lack of maintenance, or lack of response," said Rob Renner.

Officials say they are monitoring the company, Plains Midstream Canada, to ensure the cleanup is complete.

"Our expectations are clear...we expect the area to be cleaned up and re-mediated and we want to make sure they have the right people in place to do that," said Trevor Gemmell with Alberta Environment. "We take these types of incidents very seriously no matter what the size."

The ERCB says pipeline leaks are rare, but this one is the largest in Alberta history.

With files from Serena Mah