School Stinks! an Investigation of Sewer Gas Odors at a Colorado Middle School

Tuesday, June 21, 2016: 10:50 AM
Tubughnenq' 3, Dena'ina Convention Center
Dara Burris , Colorado Department of Public Health and Environment, Denver, CO
Mike Van Dyke , Colorado Department of Public Health and Environment, Denver, CO
BACKGROUND: After a Colorado middle school opened in August 2010, occupants began smelling sewer gas periodically. Multiple building modifications over the next four years did not completely eliminate this intermittent issue. This long period of intermittent unpleasant odors combined with employee and student concerns about their health created an emotionally charged situation. In 2015, the district asked the Colorado Department of Public Health and Environment (CDPHE) to assist the county health department and private consultants in investigating the source of the odors and potential health effects. After inspections to determine the likely cause of the odors, the school district made the recommended building adjustments to prevent further sewer gas infiltration though the emotionally charged situation continued.

METHODS: In order to ensure building adjustments resulted in improved indoor air quality, we recommended surveying all school employees on odors and health symptoms at four different time points, in addition to extensive air monitoring. We identified baseline rates of health symptoms at the school and compared rates of health symptoms over time. We conducted online surveys of the about 70 employees in April, September, and November 2015 and will conduct another survey in January 2016. 

RESULTS: Overall, indoor air quality concerns, reports of sewer gas odors, and health symptoms were highest in April. Most health symptoms decreased on the September survey, and then decreased further on the November survey. No one reported frequent sewer gas odor concerns on the November survey. On the April survey, those who smelled the odor were about twice as likely to report a health symptom as those who did not smell the odor which suggested a possible association between the odor and the health symptom. On the September survey, the prevalence of symptoms was similar among those who smelled the odor and those who did not. These findings in combination with air monitoring results indicate that building modifications have likely eliminated the source of the odors. The presentation will also discuss results of the January 2016 survey. 

CONCLUSIONS: To date, reported health symptoms from the survey do not clearly suggest a significant chemical exposure other than periodic episodes of sewer gas infiltration. The final survey in January 2016 will provide more data on this issue. This response illustrates the importance of continued follow-up in emotionally-charged indoor air quality situations.