SAN FRANCISCO (KPIX 5) — It may come as a surprise to many commuters and tourists that the Golden Gate Bridge has only completed part of its retrofit work.

It has been nearly three decades since the Loma Prieta earthquake shook the Bay Area. The massive quake caused fires in San Francisco’s Marina District, toppled sections of Interstate 880 in Oakland, and collapsed a large section of the eastern span of the Bay Bridge.

Since then the Bay Bridge, and the six other Bay Area bridges overseen by Caltrans, have all been re-built, replaced or retrofitted to withstand another Loma Prieta magnitude earthquake.

Golden Gate Bridge, Highway and Transportation District GM and CEO Denis Mulligan told KPIX 5 the tragic events surrounding 9/11 pressed the pause button on retrofit plans.

Still, 9/11 was 16 years ago. In that time, both the southern and northern approaches were strengthened. But the main section of the bridge, arguably its most important section, which encompasses the entire 4,200-foot long suspension span – including both towers – has not been secured.

“We have gone through and retrofitted the most vulnerable parts of the bridge first,” explained Mulligan. “So, today, if you are on the bridge in the mother of all earthquakes, you will be safe.”

In other words, Mulligan says anyone on the bridge at the time of a major quake, will be able to get off. But the bridge may be out of service for a while, potentially a long while.

Mulligan says as it stands now, the retro-fit plan includes six years of potential work. It would have to be completely finished before it could be opened to cars.

Mulligan explained that part of the delay was all about design. Engineers had to custom-build massive shock absorbers, called dampers, to help the bridge withstand a major quake.

The total cost of the work is staggering. It will take $600 million to make the Golden Gate Bridge earthquake ready. Even if the bridge district wanted to start the work tomorrow, it doesn’t have the money to do it. The district is a stand-alone organization, and federal or state help is not guaranteed.

In fact, when KPIX 5 asked both the Governor’s office and the state Secretary of Transportation to comment, both declined and issued a joint statement which reads:

“Thank you for reaching out to both CalSTA and the Governor’s Press Office on this issue, as you know the Golden Gate Bridge is not operated by the State. It’s run by a regional body, responsible for its tolls and maintenance. At this point, it would be inappropriate for us to offer comment for your story. We would respectfully defer to the Golden Gate Bridge and Highway District for comment.”

Randy Rentschler from the Metropolitan Transportation Commission said he feels that if the Golden Gate Bridge were managed by the state, the work would most likely have already been completed. But Rentschler was also quick to point out that getting state or federal funds was going to be tough.

“The amount of money lying around in Sacramento and Washington, DC isn’t that easy to get,” explained Rentschler. “So when you are talking about trying to raise $600 million, it’s going to be hard.”

Mulligan said the District is working on a funding plan right now and it hopes to start the much needed retro-fit work sometime in 2018.