Louis Temporale runs his hand over a striking Art Deco scene carved into the south side of the Air Canada Centre. He's enraged as pebbles rain down.

"This is one the most famous pieces," he says. He's referring to a stone etching of a plane, as a chunk of stone the size of a quarter falls off in his hand, "It has a long, long, long history. It's in terrible condition. It's disintegrating."

The work was done by his father, Louis Temporale Sr., who carved the bas relief in 1938-39 on what was then the Toronto Postal Delivery Building.

Slightly higher than eye level, the images that wrap the building's south facade depict scenes of Canadiana: voyageurs, the CN train used during the Royal Tour in 1939 and a postal worker, a nod to the building's origin.

The carvings at the top of beavers, maple leaves and Canada geese are also Temporale's work.

Temporale Jr., who was trained by his father and is also a sculptor, said he was hired by Maple Leaf Sports and Entertainment in 1998, four years after his father's death, to restore the art.

"I pushed for glass protection and protection in the winter but they never did it. For 20 years I've been arguing."

When the ACC was built, the south and east facades of the Toronto Postal Delivery Building were preserved as part of the new arena to comply with the Ontario Heritage Act. (CBC) When the Air Canada Centre was built in the late 90s, most of the old postal building was demolished, but the south and east facades were retained as part of the new arena for the Maple Leafs and Raptors.

The site is covered by Ontario's Heritage Act, which requires preserving and protecting heritage sites and their characteristics in perpetuity.

It also falls under the supervision of the city, which "requires the protection of the bas reliefs created by Louis Temporale in the late 1930s," said Mary MacDonald, manager of the city's Heritage Preservation Services.

Temporale Sr., who also created work housed in the National Gallery, is an Order of Ontario recipient.

MacDonald told CBC News she's aware of what she called "the weathering of the bas reliefs," that she attributed to road salt that comes off the Gardiner Expressway.

'They will be completely destroyed'

The city says it is working with MLSE to come up with a solution but Temporale said delays are a continuing threat, especially with another winter about to take its toll on the artwork.

After CBC News inquired, MLSE issued a statement paying homage to the bas relief carvings.

"Protecting and preserving that history connected to the building is more than just a priority for us, it's a mandate. We have been working jointly with Toronto's Heritage Preservation Services and expert conservation and architectural consultants to determine the most effective methods to preserve the carvings while maintaining the structural integrity of the building."

MLSE says it is working with the city to find ways to preserve the work of Louis Temporale Senior, but his son says more delays might permanently damage the carvings. (CBC) Referring to what has been a time consuming process, MLSE promised there would be a solution in place by sometime in February.

The details are still in the works though MLSE plans to cover the works, possibly with glass, but that made Temporale panic.

"It's all pockmarked. The binders in the material are disintegrating. Behind all this carbon is unstable stone. To cover them in this condition, they will be completely destroyed. The moisture will come to the surface and the salt will re-crystalize."

MLSE said the covers are an immediate solution though it is working with conservation consultants to determine how best to ensure the long-term preservation of the work.

MacDonald, whose department must work with MLSE, said the organization can't proceed with any plan yet. "As we have not yet completed our review, we can't approve the proposal," she said.