IUSD’s planned fifth comprehensive high school was once again the topic of an in-depth discussion at Tuesday night’s Board of Education meeting. Among the key takeaways this time around, staff members and planning consultants affirmed that the potential location known as Site A -- owned by Heritage Fields, developer of the Great Park Neighborhoods, and situated near the northeast border of the Orange County Great Park -- has undergone a rigorous environmental review and will likely be cleared by the Department of Toxic Substances Control in early April. Approval by the California Department of Education would presumably follow. By contrast, the alternate location known as Site B, which is on west side of the former El Toro base, could require extensive environmental mitigation. IUSD has been working with Heritage Fields to carry out the terms of agreements that call for construction and operation of a fifth high school on property to be transferred from Heritage Fields to IUSD. The campus would serve students generated by the Great Park Neighborhoods and accommodate other enrollment growth within IUSD. Meanwhile, the agreements also call for kindergarten-through-eighth-grade facilities to be constructed to serve incoming Great Park Neighborhoods students. But even with Site A emerging as the preferred option for the fifth high school project — if not the only viable option — there are no guarantees that IUSD can start construction in June of this year as planned. Lloyd Linton, IUSD’s director of facilities planning and construction, outlined four construction schedule scenarios for the board based on when the district might officially acquire Site A. Under the first two, which are possible if the land is secured by either April 30 or August 15, the campus could be completed on time for its scheduled opening in the fall of 2016. Beyond that, the completion date would be pushed further into the 2016-17 school year. While IUSD will continue to abide by the terms of the agreements with Heritage Fields, the board, on the motion of member Michael Parham, voted unanimously to create another possible scenario Tuesday night, directing staff to confer with the neighboring Saddleback Valley Unified School District to determine if it’s feasible to transfer land to that district. Such a scenario would not impact families currently living in IUSD. “I look at this and I say, either we have a school that’s built immediately and ready to fill,” Parham said, “or we cede the land to Saddleback and let (students) go to another school.” IUSD has indicated it must open its fifth comprehensive high school by fall 2016 to accommodate development from the Great Park Neighborhoods, as well as other developments, and to avoid crowding at Irvine, Northwood, University and Woodbridge high schools. With the planning process spanning several years, the district and its developer partners have agreements in place for the 40-acre Site A. Meanwhile, a member of the Irvine City Council has advocated for the alternative Site B, but that property has not been fully removed from the EPA’s Superfund list of hazardous sites. A boundary change could eliminate the need to move further with either site by shifting the incoming residential development to the Saddleback Valley district. But that possibility is only a topic of discussion at this point, as the board’s vote merely directs staff members to open a dialog with their Saddleback Valley counterparts. Moreover, IUSD would still need to open a fifth high school eventually because more growth is anticipated. For that reason, the board also directed staff to explore land acquisition options with the Irvine Company. While school districts generally hold a favorable view of enrollment growth, board member Parham expressed concern that new homes to the north might bring in more students than projected, and that could jeopardize the high school experience for the families IUSD has already been entrusted to serve. “I’m not getting comfort that we’re going to have enough seats,” he said, “and I’m not getting comfort that (our current) middle school students aren’t going to get stuck in a very overcrowded high school.” Board President Sharon Wallin agreed, noting that the district was also planning on building a K-8 school and perhaps another elementary school and middle school on the former site of the El Toro Marine Corps Air Station. “That’s a lot of schools in the area,” she said. “Look at how long it took to determine that (Site A) is a clean piece of land. Every single site, we’re going to be going through this because it’s all going to be on the base.”