BACKGROUND: In May 2016, a school was evacuated for a possible natural gas leak. Subsequent air quality testing detected elevated carbon dioxide (CO2) and benzene levels. An abandoned oil well adjacent to the school was determined to be the CO2 and benzene source. Staff and students were transferred to another school for the remainder of the school year. We investigated to identify staff and student health effects associated with CO2 and benzene exposures.
METHODS: Staff and parents were emailed a questionnaire to assess symptoms associated with exposure to CO2 and benzene during two time periods: the week before evacuation and the week after evacuation. Respondents were classified as symptomatic if they reported ≥2 symptoms. Using Chi-square tests, we determined whether symptoms were more frequent before or after evacuation, as well as the association between symptoms experienced and primary classroom location in school.
RESULTS: Respondents included 92% of staff (45/49) and 49% of students (84/171). More respondents reported symptoms before evacuation, (40/129 [31%]) than after (24/129 [19%], P = 0.001). Among respondents with primary location information (98/129), the proportion of symptomatic respondents was higher among those in the middle or high school (14/38, 37%) classrooms, where testing indicated higher levels of CO2 and benzene, than in the elementary classrooms (11/60 [18%], P = 0.04).
CONCLUSIONS: Staff and students experienced symptoms likely associated with CO2 and benzene exposure, which decreased after changing schools. For the safety of the staff and students, the school remains closed until mitigation is complete and CO2 and benzene meet minimum risk levels.