The six teachers were working at Mount Baker Secondary School in Cranbrook in 2004 and 2005.
They say they were poisoned by long-term exposure to mercury in the school's science labs and other parts of the building.
They claim they've suffered profound fatigue, headaches, joint pain, insomnia, tremors, memory loss, respiratory problems and several other symptoms.
Their application for compensation was rejected by the Workers' Compensation Board in 2010, but on Tuesday the B.C. Supreme Court ruled the teachers were entitled to a new hearing.
Justice Saunders ruled the WCB panel "was patently unreasonable in failing to weigh all of the relevant evidence, and in imposing a requirement that mercury poisoning be proven, as that diagnosis would be made by physicians."
B.C. Teachers Federation president Susan Lambert applauds the decision but says a long road lies ahead for the six teachers.
"I hope that the school board does not appeal this ruling, it's been very difficult on these teachers to pursue this case for so long, while their health has been compromised, I hope this ruling will allow them a fair hearing with the workers compensation board without further delay," said Lambert.
A date for the new hearing hasn't been set.