A proposed downtown apartment complex development by Anthem Properties is raising concerns among some Hillhurst and West Hillhurst residents.

But it’s not because of density; it’s what lies beneath the surface.

“We are determined that no building will take place, no digging will take place until we have some really firm answers,” said resident Helen Henderson.

The proposed complex of three buildings of four to six storeys and 269 housing units would be built on the former SRC site along Westmount Boulevard NW.

A former wood preservation facility on the south bank of the Bow River, which operated for a century, left behind approximately two million liters of creosote.

It seeped into the ground and migrated under the Bow River to communities on the north side.

However, the plume lies deep beneath the Earth’s surface.

“It’s pretty profound,” said Dr. Court Sandau, an environmental chemistry expert and owner of Chemistry Matters.

“It kind of follows the bedrock and is a few meters below the surface.”

Sandau says the developer will have to be careful how deep he digs.

“If the builder is aware of this and takes appropriate precautions, the shallow depth they are digging to should hopefully be above the creosote plume,” he said.

He says this should not have serious consequences.

“It takes high concentrations and prolonged exposure to see these adverse health effects from an inhalation perspective, where you breathe something in,” Sandau said.

Anthem says it will need to dig around three meters deep to build its single-storey car park, leaving 1.2 meters above ground.

“We are working with Alberta Environment,” said Rose-Mary Damiani, Anthem’s director of development.

“There is an approved risk management plan for this site and it is managed by Alberta Environment. We are currently in discussions with them about this site, this plan, and we are reworking it or modifying this plan to take into account the form of construction which is now proposed.”

Damiani says he monitors the site.

“So the risk management plan for this site includes testing, reporting, monitoring and exposure control protocols,” she said.

Regional councilor Terry Wong says the city is aware of the proposed plans for the site and the possible impacts.

“We have discussed with the developer how he will be able to build without impacting the ground below,” he said.

An open house at the Hillhurst-Sunnyside Community Association was held Wednesday evening.

Residents received an update on the Anthem development permit.

If the proposal is approved by the city, construction could begin as early as next summer and be completed in 2028.