In January 2010, the CTA heralded the end of the $530 million Brown Line reconstruction project with a ribbon-cutting ceremony featuring then-Mayor Richard M. Daley and a host of dignitaries.

Turns out they were a tad premature.

The massive restoration effort included new wooden platforms at 14 stops on the train route, which stretches between Chicago’s North Side and downtown. But because the transit agency inexplicably chose a flame retardant that didn’t protect the wood planks against the elements, the new L platforms ended up rotting – and all but one have been or will be replaced after just a few years of life, the Better Government Association has learned.

The added cost to taxpayers? Roughly $6 million, the BGA found.

State Rep. Cynthia Soto, a Chicago Democrat who chairs the Illinois House Mass Transit Committee, which helps regulate and fund public transit in the region, described the added expense as “shocking.”

“Why couldn’t we do it right the first time?” she said in an interview. “It’s a lot of wasted money. It will irritate a lot of people when they hear this.”

The CTA acknowledged its people screwed up by not having suppliers or contractors coat the wood with weather sealant – which would have guarded against rain, snow, wind and the like – but said the mistake was made during the previous regime, when Daley controlled the CTA.

With Rahm Emanuel the mayor now, “this administration took quick and cost-effective steps to properly address the issue and ensure customer safety – for the long term,” said CTA spokesman Brian Steele.

Which means planks with cracks, holes and splintering have been or will be replaced with properly sealed material at 13 stations – all of the wooden Brown Line stops but Wellington. (There also are five stops with concrete platforms.)

undefinedPhoto Gallery: Click to Enlarge

CTA officials initially noticed rotting wood in August 2008 – two years after the first Brown Line stations were completed. The BGA first reported on the problem in December 2010, at which time roughly $300,000 had been expended to replace deteriorating wood.

Since then the problems and price tag have escalated.

But Steele said $6 million should be the final tally for material and labor. (To put this in perspective, new CTA rail cars cost roughly $1.5 million apiece. What’s more, the agency is planning sizable fare hikes starting next month on some passes and Blue Line trips.)

The platform funding is coming out of the annual facilities maintenance budget, Steele said, adding the employees responsible for the foul-up are no longer with the CTA.

New, properly treated planks have been installed everywhere they need to be except the Diversey L stop. Work there should be done in January, Steele said. The new platforms should last at least 20 years without significant decay or a need for new sealant, he said.

While no injuries have been reported because of pocked platforms, commuters certainly have noticed the problems on the line, which handles more than 100,000 rides on the average weekday.

“There was actually a hole for awhile,” 31-year-old rider Molly Rand told the BGA, referring to the Southport L stop that in recent days was overhauled. “Seems like just a big waste of money and time.”