By Emory Bryan, News On 6
TULSA, OK -- With rain in the forecast there's a good chance of more stains on the BOK Center.
It's covered with stainless steel, so why is it stained?
Shortly after the BOK Center was finished, stains started streaking down the walls.
They're only underneath the windows.
The builder says that's because the caulk around the windows is "bleeding" silicone.
That allows dirt to stick to the otherwise stainless steel exterior.
Dow Chemical made the caulk, but the builder says the company doesn't know how long it will take to fully cure.
"They do say that eventually it will expire the bleeding. It won't continue, but no one is willing to commit to how many years that will be," said Bart Boatright with Tulsa Vision Builders.
In the meantime, the BOK Center has started a new, labor intensive effort to clean off the stains.
It was delayed while 14 different chemicals were tested to see what would remove the stains without damaging the building.
It turns out only muriatic acid will take off the stains, but it's strong enough to make the shingles rust.
That complicates the cleaning because the acid has to be quickly washed.
"We'd rather there be another product that would magically remove it, but we haven't been able to determine that," said Boatright.
Boatright said it was not known it was going to bleed like this when it was installed.
The new cleaning plan started Monday and will be repeated as often as necessary, probably for several years.
The cleaning job started on the west side in a less visible spot to make sure it works and later in the week they'll move around to the east side where the worst stains are, unfortunately most visible by the main entrance.