Barrels containing an unknown, foul-smelling liquid have been unearthed in Guelph.

They were discovered Tuesday by a construction crew preparing to install a water main in the area around Wellington Street and the Hanlon Parkway.

Initially, two 170-litre drums were found – one of which had been punctured and was leaking.

Wednesday, another four barrels were discovered.

“We have sent the samples to a chemical test lab,” Majde Qaqish, a city engineer, tells CTV News.

The city is working with the Ministry of the Environment to determine the contents of the barrels.

As a precaution, the area around the discovery has been covered in tarps and air quality is being watched closely.

“We don’t want to move things from the site until we understand what the material is all about,” says Qaqish.

At this point, officials have few clues to go on aside from a belief that the area was once a landfill.

Mary Rae Jobbitt-Mills, who lives near the work site, describes the liquid as a dark green film that was “floating” on water.

She says she’s worried the contents of the drums may be causing headaches, itchy eyes, dry mouths and other issues.

“We’re concerned that it’s impacting our health,” she says.

Results of tests conducted on the liquid are expected by the end of the week.