Now authorities suspect that smell caused the death two hours later of 59-year-old Phillip Hennig, after an ammonia pipeline leaked in the nearby area.
Fire officials were dispatched to the site shortly after the leak was confirmed.
The surrounding area was evacuated, according to a written statement made to CNN by Burt County Sheriff Robert Pickell.
The Centers for Disease Control and Prevention says anhydrous ammonia
is a pungent gas with suffocating fumes that is used as a fertilizer.
When released, the vapors initially move close to the ground, causing greater risk for exposure.
Bruce Heine of Magellan Midstream Partners, the company who owns and operates the leaking pipeline, said the incident is under investigation with the National Transportation Safety Board.
Eric Weiss, a spokesperson for the NTSB, confirmed the agency is investigating the incident but cannot provide immediate detailed information.
Duty Officer Brandon Weatherly of the National Response Center, a federal point of contact for environmental discharges, said the center received three reports of the leak.
Terry Schroeder, an emergency manager for Burt County, confirmed with CNN affiliate KETV that the incident forced a number of families to be evacuated and that a nearby highway was closed.
Magellan reported that
about 40 residents in 23 homes were told to leave the area.
According to KPTM, the pipeline company will pay the families' expenses.
As of Wednesday morning, the pipeline company said it had 50 employees on site alongside federal regulators and state and local emergency responders. The pipeline section where the leak occurred was shut down.
"Progress is being made on repairs at the release site and air quality readings continue to improve," the company said. "It is our goal to completely isolate the failed portion of the pipeline (Wednesday), which will allow the reopening of local roadways."
Those evacuated have not been able to return.
"No one is allowed in the area of the leak until further notice," Pickell said in a statement Wednesday afternoon.
The incident is still under investigation.