Snakes as an Indoor Air Quality Issue: iSi's Memorable Projects
At iSi we get the opportunity to come across all types of industrial hygiene and indoor air quality projects.
At iSi we get the opportunity to come across all types of industrial hygiene and indoor air quality projects. One of our most memorable ones involved something that isn’t typically thought of as a indoor air quality problem: snakes!
⚡ TL;DR: An office building in Chapman, Kansas had black racers nesting in ductwork, causing foul odors and worker discomfort. iSi worked with a wildlife biologist to identify the source, then recommended prevention (drift fences, pea gravel) and removal (glue traps, relocation 2+ miles away). In 2 days post-visit, staff caught 23 snakes, eliminating the issue.
⚠️ The Pain: Unusual indoor air quality problems are often misattributed or ignored. Employees complained of mysterious odors but didn’t know the cause—leaving management unsure whether to investigate HVAC, mold, chemicals, or animal issues. The problem festered for months until proper diagnosis identified the real source: building envelope gaps that allowed wildlife entry.
In Chapman, Kansas, employees at a 1930s office building were complaining about an unpleasant odor in the building. The employees suspected that the odor was coming from snakes that were nesting in and around the building. In the spring and fall over the past several years, employees frequently caught snakes in the building. The snakes often poked their heads out from the ductwork and slid over toes at work stations.
The snakes were confirmed to be black racers, which produce a distinctive odor when they are disturbed or active. Some settling asphalt near the building provided a place for the snakes to den, and some snakes found paths which allowed them to enter the building. With winter approaching, the snakes had no reason to leave once inside the building.
iSi’s Industrial Hygienist, Constance Timmons, met with a local wildlife biologist from Kansas State University to do a walkthrough evaluation of the building to gather background information. With the indoor air quality information that they gathered, Constance and the wildlife biologist determined that the odor was in fact due to snakes. Although the odor was not a health hazard, iSi recommended ways to prevent the snakes from re-entering the building in the spring such as using snake traps; a drift fence between the building and the field, consisting of silt about an inch deep; and using pea gravel as a filler around the building because it does not support tunnels.
For ongoing snake control, iSi recommended placing glue traps along the inside walls of the building, making sure that the traps are not adjacent to standing pipes. A snake is able to wrap around the pipe and leverage itself off the trap. Also, turning up the heat in the building may increase the capture of snakes on the glue traps because they are not able to hibernate when they are so warm.
Building personnel were advised that, if they chose to relocate the snakes, to release them at least two miles from the building during any season but winter. Racers have a home range of 25-50 acres, and would find their way back if not released far enough away.
In the 2 days after our visit, the employees were able to catch over 23 snakes!
If you’re experiencing persistent unexplained odors, unusual occupant complaints, or HVAC problems that don’t resolve with standard maintenance, the cause may not be mechanical. Wildlife intrusion, building envelope gaps, and unusual contamination sources often masquerade as HVAC failures. A qualified industrial hygienist can distinguish between mechanical and environmental causes, saving you thousands in unnecessary HVAC work.
If you’ve got an indoor air quality issue, we feel like we’ve seen it all! Let us diagnose the problem and find the solutions.
Frequently Asked Questions
Q: What unusual indoor air quality issues can affect workplace environments?
A: While most indoor air quality issues involve HVAC systems, ventilation, or chemical off-gassing, unusual issues can include animal nesting (snakes, birds, rodents) in ductwork and wall cavities. Black racers, for example, produce distinctive odors when active, and their presence indicates building entry points that could affect air quality and worker comfort.
Q: How did iSi identify the source of the odor in the Chapman, Kansas office building?
A: iSi’s Industrial Hygienist Constance Timmons consulted with a wildlife biologist from Kansas State University to conduct a comprehensive building walkthrough and assessment. Together they determined the odor came from black racer snakes nesting in and around the building’s ductwork and structure, entering through gaps and holes.
Q: What prevention measures did iSi recommend for the snake problem?
A: Recommendations included installing snake traps, creating a drift fence with silt between the building and field, using pea gravel around the building perimeter (which doesn’t support tunneling), placing glue traps along interior walls, and ensuring traps were not adjacent to pipes (which snakes could use for leverage). Relocation required moving snakes at least two miles away during appropriate seasons.
Q: How can facilities conduct comprehensive indoor air quality assessments?
A: Facilities should engage qualified industrial hygienists to investigate unusual odors, assess building envelope integrity, review HVAC system design and maintenance, and identify potential entry points for animals or contamination sources. iSi Environmental conducts thorough assessments including visual walkthroughs and expert consultations.
💰 IAQ Assessment ROI: A professional indoor air quality assessment costs $2,000–$8,000 and identifies root causes of odor complaints, HVAC failures, and occupant health issues. Facilities that skip assessment often spend $20,000–$100,000+ on unnecessary HVAC replacements, remediation, or emergency repairs. Early diagnosis prevents wasted capital spending.
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