OSHA investigates carbon dioxide complaint at South Fork High School

An OSHA inspection is underway at South Fork High School in Miranda after a complaint about carbon dioxide levels that were reportedly above state limits, putting one of Southern Humboldt’s most visible public schools under fresh scrutiny over indoor air safety.

The concern goes beyond comfort. OSHA says school indoor air quality can affect the health, performance and comfort of school staff and students, and the CDC says ventilation is an important illness-prevention strategy in schools and childcare programs. In a high school where students and staff spend long hours in classrooms, labs and shared indoor spaces, elevated carbon dioxide can signal poor ventilation, stale air, fatigue and reduced concentration.

Federal OSHA lists carbon dioxide’s permissible exposure limit at 5,000 parts per million as an 8-hour time-weighted average. California’s Division of Occupational Safety and Health says it investigates workplace indoor-air-quality complaints that may be injurious to building occupants. That makes the complaint at South Fork more than a building maintenance issue: It is now a workplace and student-health question with regulatory consequences.

A source said the district knew about the carbon dioxide problem as early as September, raising the possibility that students, teachers and staff were exposed for months before outside oversight began. If that timeline holds, families in the Southern Humboldt Joint Unified School District will want to know what was measured, what was reported internally and what steps were taken while the issue remained unresolved.

Southern Humboldt Joint Unified is based in Miranda and includes South Fork High School among its schools. In a rural district where facilities work can be expensive and difficult to schedule, the complaint highlights a familiar local tension between aging infrastructure and the speed of accountability when safety concerns surface.

The inspection is still active, and the outcome has not been announced. For now, the key questions are whether the school’s indoor air conditions exceeded allowable limits, how long students and staff were affected, and what Cal/OSHA and the district do next to document the problem and correct it.