SEATTLE -- The tunnel-boring machine Big Bertha has been stuck in neutral for more than a month now, and the Washington State Department of Transportation still doesn't know why.
On Wednesday, three crews of five trained divers were to work around the clock to get up close to Bertha's cutter head using a hyperbaric chamber.
"The workers need to go into these hyperbaric manlocks; they go in there and increase the pressure," said Seattle Tunnel Partners project manager Chris Dixon.
There's up to 50% more pressure underground than on the surface so it will be a slow and careful process for divers.
"We a very confident that it's going to give us the ability to assess what the situation is," Dixon said.
But underground, crews will have limited vision.
"We are not going to be able to determine maybe what's 5 or 6 feet out in front," Dixon said.
As WSDOT waits for a solution to get Bertha moving again, the pressure is on the contractor, Seattle Tunnel Partners, which could possibly face a lawsuit.
State Transportation Secretary Lynn Peterson sent a letter to lawmakers and a part of it reads:
"WSDOT has had concerns about the machine's operations and critical systems since its launch on July 30, 2013. We have discussed these concerns with STP frequently over the past five months and this week sent a formal letter stating our concerns and asking STP how they will address them prior to tunneling under the viaduct and downtown. We are providing you with this information in lieu of a copy of the letter because it could be the subject of a potential future litigation between WSDOT and the contractor."
The agency wanted a series of answers from the contractor by Wednesday, including how they would make up for lost time.
"They are going to blame somebody. You know, somebody is going to pay for this," said Luigi DeNunzio, owner of Al Boccalino restaurant in Pioneer Square.
Business owners in the area say their livelihoods depend on a quick solution.
"Whether the project works or doesn't work, we are at their mercy," DeNunzio said.
More than a month after the project stalled, crews still don`t know what's blocking Bertha.
They say it's possible it's a long steel pipe. Earlier this month, they discovered a part of it protruding from Bertha's cutter head.
WSDOT says the pipe was installed by their crews in 2002 to study the flow of groundwater but it might not be the only problem.
"Absolutes in this kind of industry is not where we want to go. It is kind of like a medical diagnosis, they have to do a certain amount of things," WSDOT program administrator Todd Trepanier said.
Seattle Tunnel Partners says the hyperbaric intervention could take several days and they hope to have a better picture by then.
Peterson will appear before the state Senate Transportation Committee Thursday afternoon to try to answer legislators' questions about the project.