Ala Moana Center management officials estimate it will cost about $4 million to make repairs and improvements to faulty railings at the state’s largest shopping mall, and the work will likely run well into, if not beyond, the holiday shopping season.

The center is undertaking the improvements after a 21-year-old man died and another man was critically injured Oct. 9 when the railing they were leaning on in the Hookipa Terrace section of the mall collapsed, causing them both to fall several stories.

A notice of violation was issued by the city Department of Planning and Permitting against mall manager GGP Ala Moana LLC, giving the company 30 days to obtain a building permit and repair the faulty railings or risk fines.

But GGP requested and was granted a 30-day extension through Dec. 14, DPP spokesman Curtis Lum said.

Ala Moana management has submitted a building permit application to repair and replace railings throughout the mall, and “we are awaiting plans” that accompany the application, Lum said.

The application lists the estimated cost of the repairs at $4 million.

Acting DPP Director Art Challacombe, through Lum, said the mallwide repairs might not have to be completed by Dec. 14 so long as the company can show significant progress.

Francis Cofran, Ala Moana general manager, declined to say how many railings or what percentage of the mall’s railings are being replaced, or where faulty ones are located.

But in a statement, Cofran said “Ala Moana Center’s structural engineer has completed a thorough assessment of all railings on property and all areas of concern have been secured.”

Cofran also confirmed that Ala Moana has initiated the building permit application process.

After the railing collapse last month, inspectors from the Department of Planning and Permitting found evidence of rust where the collapsed rail was embedded in the concrete, as well as on other railings in the general vicinity.