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Mysterious Odors

Updated: Feb 11, 2020

I was contacted recently by a building management firm in my hometown of Dover, NH for whom I have done IAQ assessments in the past. They asked if I was available for an “emergency odor problem” in a building they own and manage, so I arrived later that afternoon for an assessment.

The industrial space is 45,000 square feet with an average ceiling height of 20 feet, which is about 900,000 cubic feet. I met two owner reps and three men who work in the building. I was told that the mysterious odor was mostly concentrated in the middle of the space. When I arrived, the odor was faint due to open doors and fans operating to reduce the odor. That morning an HVAC tech did an inspection using his combustible gas detector, that first went off when he entered the building but then settled down. He said it was not natural gas. Everyone searched the area for the odor but could not pinpoint the source. I offered to return the following morning to gauge the odor's strength at that time.

I arrived at 6:00 a.m. the next morning and saw the two workers from the previous day outside by their vehicles. They were outside because the odor had become unbearable indoors. I used my combustible gas detector and calibrated it to the outdoor air for five minutes, per the instructions. When I entered the side entrance my detector “screamed” that there was a problem and the odor was noticeably intense. I set up two Prism VOC air pumps: one where I was told the odor was most intense and one near the side employee entrance. I continued to search for the source of the odor and recalibrated my detector to the polluted indoor air near the entrance. The detector peaked near the location where the odor was supposedly most intense.

I reported my findings thus far to the building owner and recommended they call the gas utility to verify if the odor was natural gas or not. The building owner decided to call the fire department. In about three minutes, two hook and ladder trucks, one emergency vehicle and about ten firemen were on site and I met them at the door and we entered the space together. The lieutenant immediately said, “That is definitely natural gas,” and called the gas company. However, the remaining firemen were not convinced because their detectors did not indicate natural gas. We toured the rest of the building and I pointed out the alleged source point. About fifteen minutes later, one of the firemen opened the cover on a machine and discovered a small Duracell Lawn and Garden battery that had overheated (see picture). Once we smelled near the battery, there was no doubt it was the source of the odor. But how such a small battery could pollute that large volume of air in the building is a mystery.

The moral of the story is never write off anything as the source and never leave any stone unturned. Anything can cause an odor!

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