ANDOVER, Minn. — Reports of a strong natural gas odor in Andover on Tuesday evening prompted a coordinated, multi-agency emergency response that concluded without injury, evacuation, or environmental hazard, according to officials from law enforcement and regional utility providers.
The Anoka County Sheriff's Office, working alongside utility partners, confirmed that the situation was fully resolved by 9:00 p.m., when emergency services formally stood down and returned to normal operations. Responsibility for the scene was then transferred to utility crews for continued precautionary monitoring.
Incident timeline: December 30, 2025
The incident began in the early evening after residents reported a pronounced odor consistent with natural gas, along with initial concerns about a possible chemical exposure.
In the early stages, deputies from the Anoka County Sheriff’s Office and crews from Northern Natural Gas initiated an investigation. Authorities advised residents that there was no reason to evacuate and that no immediate protective actions were required.
By 7:30 p.m., CenterPoint Energy reported that preliminary testing had not detected any active gas leaks. Officials also confirmed that earlier reports suggesting a chemical spill were unfounded. As a precaution, CenterPoint deployed additional detection equipment to conduct a broader and more comprehensive search of the area.
At 9:00 p.m., emergency services transitioned back to standard operations. Utility providers reported no leaks detected, and CenterPoint Energy remained on site to continue monitoring conditions.
Coordinated response
The response involved several agencies, each with defined roles focused on public safety and infrastructure integrity:
Anoka County Sheriff’s Office managed public communication, scene coordination, and overall situational oversight.
CenterPoint Energy, the primary local gas utility, conducted leak detection and infrastructure safety assessments.
Northern Natural Gas, which operates high-pressure transmission pipelines supplying regional utilities, inspected its assets in the area.
Local fire departments were staged nearby during the investigation to address any potential fire or hazardous materials risk if conditions escalated.
No injuries were reported, and no service interruptions were announced.
What likely caused the odor
While investigators determined there was no active gas leak, officials noted that incidents of this kind can stem from several well-documented technical or environmental factors.
Natural gas is odorless by itself. Utilities add a sulfur-based odorant called mercaptan so leaks can be easily detected. In some cases, a temporary concentration of this odorant, sometimes referred to as an odorant slug, can occur during routine maintenance or pressure changes, creating a strong smell even when gas is not escaping.
Cold weather conditions can also play a role. Atmospheric inversions common in winter can trap air close to the ground, allowing routine or minor odors to become more concentrated and noticeable over a wide area.
In addition, reports of chemical spills are sometimes triggered by nearby use of industrial solvents, fertilizers, or other materials. In this case, on-site testing ruled out those sources.
Safety guidance for residents
Although no emergency actions were required during this incident, authorities reiterated standard safety guidance for any situation involving a suspected gas odor.
Residents are advised to leave the area immediately if they smell a strong “rotten egg” odor associated with natural gas. They should avoid using phones, lighting matches, or operating light switches inside the affected area, as even small sparks can pose a risk. Once at a safe distance, residents should call 911 and contact their gas utility’s emergency line.
Officials emphasized that prompt reporting, combined with a coordinated response, allowed agencies to quickly rule out danger and ensure public safety. Further updates were shared jointly by the City of Andover, the Anoka County Sheriff’s Office, and utility partners as the situation unfolded.
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