TORONTO - The Toronto Transit Commission says the case of a worker accused of urinating on the wall of a subway station is still being investigated.

Spokesman Brad Ross says the commission received a "very serious complaint" from a customer and began a process to deal with it internally.

He says despite a statement from the union that represents transit workers in the city, the case is not closed.

The alleged incident at Runnymede station last month came to light when TTC chairwoman Karen Stintz issued a public apology, calling it "unacceptable."

Union spokesman Bob Kinnear responded Monday by calling the report "a total fabrication" and demanding an apology from Stintz and the media.

Kinnear, who heads Local 113 of the Amalgamated Transit Union, says the worker was just using his cellphone to check on a work assignment. He said an internal investigation verified that account.

But Ross said Monday that while the appropriate division spoke with the employee, there was no followup discussion with the customer on the original complaint about urinating in public.

He said that will take place within days.

"The employee says that he was on his cellphone .... so he was disciplined for the cellphone use," said Ross.

"As far as we're concerned, this matter remains open and unresolved."

As for the public urination complaint, Ross said it is a "very serious allegation" and the TTC must speak directly to the customer in order to understand what happened.

Kinnear called Stintz "unprofessional" for making the public apology and faulted the media for reporting it. He said he wants a public apology from both, on behalf of his members.

The worker involved has not been publicly identified.

"If someone thinks they saw him urinating, they were imagining it. It didn't happen," Kinnear said in a release.

Ross defended Stintz on Monday, saying she was given the information by TTC management staff.

"The chair herself has been nothing but supportive of all TTC employees, particularly front-line employees, since the moment she was sworn in as chair of the TTC, so to suggest otherwise is simply unfair," he said.