Students and parents were notified Wednesday night about the testing, so no one showed up to the campus.
The chemical TCE, or trichloroethylene, was discovered last Friday. Officials say the compound was not found in the school's drinking water and testing is expected to continue during the school's temporary closure.
Both state and county officials have confirmed that the compound came from somewhere offsite, the district said.
TCE is a solvent used for industrial cleanup. The concern is that it's vaporizing and creating a health hazard for students and staff inside McClymonds, a school that was built in 1915.
Tolani King's daughter is a senior at McClymonds.
"That's a major concern," said King, who also works at the high school as an aide. "This is quite disruptive for all the students here at the school site because missing even one day of school or a few hours of school is detrimental to their future."
The TCE incident is just the latest scare for the community in and around McClymonds.
In 2008, student testing found high levels of lead around the schools. And in 2017, the East Bay Municipal Utility District found lead contamination in the drinking water, from dated metal fixtures.
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Now that TCE has been discovered, the school will remain closed for the immediate future, while the Oakland Unified School District officials scramble to figure out when or whether it can re-open and how to accommodate McClymonds' 372 students in the meantime.
That may include holding McClymonds classes on another campus.
The district will hold an information meeting for McClymonds parents Thursday evening from 6 to 7:30 p.m. at Taylor Memorial United Methodist Church, 1188 12th St., Oakland.
The school district held a press conference Thursday afternoon to provide more information on the incident. Watch the full video below.
McClymonds High School is located at 2607 Myrtle Street in Oakland.
#Developing @OUSDNews now says @McClymondsHS in #OAKLAND may be closed into next week due to chemical issue, but classes could be held at another location. District will update press at 1:30 this afternoon. #abc7now pic.twitter.com/37DBr7gxkH— Laura Anthony (@LauraAnthony7) February 20, 2020