Deliberations for the construction of the Yale Biology Building are in the works — still.

The YBB, intended to replace the aging Kline Biology Tower, has been under discussion by faculty and administrators for more than a decade. While previous proposals saw the structure as the center for biology departments alone, the latest, in the works since the spring, envisions an interdisciplinary facility that will serve primarily as the Molecular, Cellular, Developmental Biology department’s home base, but provide lab space for physics, chemistry and engineering as well, said MCDB professor Scott Holley.

“It’s a biology building, but there’s a lot of breadth to it,” said Jim Slattery, associate provost for science and technology. “We’ve been thinking about what science is going to be 20, 30, 40 years from now. This is a chance for great dialogue about what the opportunities [for YBB] could be.”

Those anticipating broken ground in the YBB’s original site at the Lot 22 parking lot on Whitney Avenue should now shift their gazes skyward. The Gibbs building, which is set to be demolished, will be replaced with a building that houses the YBB on its top floors. The new facility will likely feature lecture halls that rival or surpass the size of OML 202, a cafeteria and core microscopy centers for research in quantitative biology, which debuted as MCDB’s newest track last spring.

But Science Hill faculty said they have reason to be less than optimistic about the YBB’s construction prospects. The project is the latest in a string of frustrating false starts for the building, which was originally slated for completion more than 10 years prior, and now has a due date in 2019.

“I feel like we’re Charlie Brown with the football, and the administration is Lucy pulling the football away at the last minute,” said MCDB professor Scott Holley, a member of the YBB committee. “On one hand, I’m happy that the YBB is a priority, but it’s so far past due.”

This latest iteration of development, once completed, will be the second time the university has finalized plans for the building; according to MCDB professor Valerie Horsley. The first design, set to go in 2008, was derailed both by the recession and a delay in city approval, she added.

Holley said he looks forward to the building’s much-needed consolidation of space for microscopy and teaching, both of which researchers will be able to conduct adjacent to one another instead of separately in OML and KBT, as they do now. The expandable and contractible lab space that comprised the original design, meant to facilitate collaboration between people in different disciplines, remains part of the plan, as does the greenhouse for the developing field of plant biology.

Rounding out the building’s residents will be four members of the physics department, who will move into a space on the bedrock level that is dedicated to optics. An aquatics facility is also in the works for E&EB researchers.

The proposed lecture halls will do their part to accommodate the 15 percent growth in Yale’s student population, which will arrive along with the two new residential colleges in 2017. Meanwhile, the MCBD department confronts the opposite problem of shrinkage. Although it lost four faculty this year — one to Harvard, one to Peking University, one to retirement and another who was denied tenure — the administration, citing budget constraints, is only allowing the department to fill one spot, Holley said. They are seeking the administration’s approval for more slots to recoup their losses and maintain the student-faculty ratio.

Steven Girvin, deputy provost for science and technology, confirmed that the project is currently on track to be finished in about five and a half years.

“That’s pretty much full speed ahead — it’s about as fast as we can go,” he said.

It remains for Yale to find a way to pay for it. Holley said that while the administration has discussed finding donors for either the building as a whole or certain individual components, it is preparing to go ahead as though it were funding the building alone. The cost, last estimated at around a quarter of a billion dollars, is still being determined, Girvin said. The university also has yet to select an architect for the project.

But Girvin said the administration is committed to finishing the YBB, as well as the long-term renovations to Sterling Chemistry Lab. Horsley said she, for one, is hopeful that the university will follow through with its promises.

“We’re moving forward with the idea that the building will be built,” Holley said.

According to OCI, there are 586 students enrolled in the introductory biology sequence this fall.

Correction: Sept. 26

A previous version of this article incorrectly stated the cost of the Biology building as around a quarter of a million dollars. In fact, it is about a quarter of a billion.