The San Francisco Fire Department official said the students were from James Lick Middle School. A couple of students were first showing symptoms of vomiting and nausea while one was found with extreme symptoms.
The San Francisco Unified School District, where the high school is located, said in a statement that its staff members “are working with emergency personnel” to respond to the incident, Xinhua news agency reported.
“At this time it appears as though some students have ingested a substance that is causing adverse reactions. There are 10 known victims who have been identified as being affected,” it said.
It is unclear what the “unknown substance” is, but the media reports said it might be related to illicit drugs.
The fire department said in a tweet that it had dispatched two Mass Casualty Transport Buses to the school for possible transportation of school kids from the impact area.