GREENBRAE -- Marin General Hospital released a draft environmental impact report for a roughly $500 million rebuild project that will bring the 235-bed level III trauma center in line with state seismic measures while improving other features.

The release of the draft EIR marks the first formal step by the hospital, overseen by the Marin Healthcare District, on the massive project, just weeks after it was declared the "prevailing party" in a dispute with Sutter Health, which operated the facility until 2010.

Now, with what was one of the most contentious health care legal battles in the North Bay finally settled, the district is moving full speed ahead on meeting the tentative construction deadline of 2020.

"It's a critically important project as the only acute-care hospital in the county," said Jon Friedenberg, chief fund and business development officer. "It's an important milestone."

The project will be financed by an approximately $350 million general obligation bond that the district hopes to have on the ballot by November 2013. If passed, Marin County residents would pay an additional $15 to $20 a year per $100,000 of assessed property value. The remaining cost would be covered by general revenue bonds and a fundraising campaign, Mr. Friedenberg said.

Construction plans call for a campus totaling over 660,000 square feet, including a new 300,000-square-foot hospital with two wings that will replace the existing structure. It would also include a 100,000-square-foot ambulatory services building and two parking structures with 919 spaces, which was modified from an earlier version of the plan that called for one large parking structure after residents raised concern.

A pedestrian bridge connecting one parking structure to the hospital and new photovoltaic trellises atop both parking structures are dependent upon the district securing enough funding.

Construction could begin in early 2015, if the bond measure passes and the permitting process goes as planned, Mr. Friedenberg said. Construction is expected to take about three years. That would allow for meeting the 2020 deadline, which was extended from 2015 by legislation.

The total number of licensed beds would remain at 235, but nearly all of them would be made into larger, private rooms. Mr. Friedenberg said that would increase both the level of care -- by allowing more physicians and equipment in the rooms -- and patient privacy as well as reduce hospital-born infections.

The trend among newly built hospitals is to have mostly private rooms, as care is delivered to the patient versus the old method of wheeling a patient on a gurney to various departments in the hospital. To that degree, the new facility would greatly enhance the patient experience, Mr. Friedenburg said.

"There's more flexibility, there's more capacity, and other benefits with privacy and preventing infectious diseases," he said. "It's going to really enhance our ability to provide state of the art care."

Additionally, operating rooms will be larger and other technological improvements will be made. Mr. Friedenberg said that regardless of the state-mandated seismic standards, the hospital would be in line for a rebuild to improve care.

"The original buildings are now 60 years old. Hospitals typically have a shelf life of about 50 years because of the way that inpatient services are provided and change. That is very much the case at Marin General," he said.

The hospital was awarded $21.5 million, plus attorney's fees, from its victory over the previous operator. Mr. Friedenberg said that while the use of that money has yet to be determined, it would likely go to a more immediate need at the facility and not the rebuild effort.

The district is still accepting comments on the environmental report, which will be discussed in an October public hearing.