An argument over a return at a local home improvement center escalated yesterday into an employee punching a customer, the victim's son said.

John Galarza of Tottenville was at the Mariners Harbor Home Depot on Forest Avenue around 3:30 p.m. with his father, also John, who lives in Richmond Valley.

The younger Galarza said he was trying to return a roll of electrical wire, but was told by an employee and manager that it was not returnable.

They began arguing -- Galarza saying that the rule was not listed on the receipt or return policy -- and the manager went to call security.

According to the younger Galarza, the female employee then started making derogatory comments to his 66-year-old father and suddenly punched him in the mouth.

Police confirmed that 28-year-old Shakima Hardy of the Park Hill section of Clifton was arrested at the Home Depot store and charged with misdemeanor assault following the incident, in which the elder Mr. Galarza was knocked to the ground and was left bleeding from the mouth.

The blow, his son noted, knocked out several of his father's teeth and caused the older man to hit his head on the concrete floor.

"She's an employee, she's supposed to represent the place," the younger Galarza said. "It's crazy."

Paramedics brought his father to Richmond University Medical Center in West Brighton, where he was told he had a concussion. He was expected to stay hospitalized overnight.

An employee at Home Depot said the store had no comment and referred all calls to the company's corporate office in Atlanta, Ga.

"We take this matter very seriously and we immediately launched an investigation," Home Depot spokeswoman Jen King said.

"At this point, we are still conducting our investigation and defer questions to the police."