Four Minneapolis police officers experienced adverse effects after breathing an unknown airborne substance inside a downtown high rise on Wednesday evening, and more than a day later no agency has said what the substance was.
The exposure happened during the response to a mass shooting at the Shoreline Plaza apartment complex, formerly known as Loring Towers, at 15 East Grant Street near Loring Park. Two people and the suspected shooter died. Three responding officers were injured, two of them by gunfire. According to the City of Minneapolis, the four officers who reported adverse effects were affected separately from the shooting itself; two additional officers were hurt when their squad car crashed while responding, and three other civilians were shot.
For residents of the building, downtown workers, and families of emergency responders, the open question is narrow but consequential. Nobody has said whether the haze that filled an upper floor was gun smoke, a discharged fire suppression system, burning material, or something released deliberately. Until it is identified, neither the exposed officers nor the residents who sheltered inside can be told exactly what they breathed or what to watch for.
The Haze Officers Walked Into
The shooting was reported around 4:36 p.m., with the first call indicating that one person had been shot, police Sgt. Garrett Parten said at a news conference. More calls followed reporting additional gunfire. Officers were dispatched and were inside the building less than two minutes later, Interim Police Chief Bill Peterson said, according to an Associated Press account of the briefing.
They found wounded people in the lobby, heard continued gunfire, and followed the sound to an upper floor. There, according to CBS News Minnesota, Parten said officers "encountered a haze that significantly limited their visibility."
Peterson was blunt about how little is known. "We don't know whether it was smoke or if there was some other event," he said, and he offered no further detail about the haze.
That is the entire public record on the substance. No agency has released air monitoring results, no hazardous materials finding has been announced, and no exposure notice has gone to residents. Four officers experienced adverse effects, but the nature of those effects has not been described beyond that phrase. Peterson said one officer was shot in the leg and another was shot twice in the abdomen, and that all three injured officers were in stable condition and expected to make a full recovery.
Unknown Exposures Change the Rules of an Emergency Response
Emergency responders train to identify a hazard before entering it. A structure fire, a chemical spill, and a shooting each carry a different protective posture. An unidentified airborne agent inside an active shooting collapses those categories at once, because officers moving toward gunfire cannot stop to put on respiratory protection without leaving wounded people unattended.
The practical consequence is that responders absorb an exposure nobody has characterized. Smoke from a fire, combustion products from burning furnishings, particulate from a discharged extinguisher, and an irritant chemical all produce overlapping early symptoms, including coughing, burning eyes, and shortness of breath, but they carry different follow-up requirements. Some resolve within hours. Others warrant monitoring for delayed lung injury that can appear well after a person feels fine.
There is also a documentation problem that outlasts the incident. Occupational health claims, and any later illness a responder attributes to that night, depend on a record of what was present. When the agent is never identified, that record does not exist.
Symptoms That Warrant Medical Follow-Up After an Airborne Exposure
Anyone who was inside the building during the response and later develops symptoms should contact a clinician and describe the exposure specifically, including the floor they were on and how long they were there. That detail matters more than the symptom description alone.
Cough, throat irritation, watering eyes, and mild breathlessness are the most common early complaints after inhaling smoke or an irritant, and they usually improve once a person is in clean air. Symptoms that should prompt medical evaluation rather than waiting include worsening shortness of breath, chest tightness, wheezing that is new for that person, coughing up discolored sputum, confusion, or a headache paired with nausea. Difficulty breathing at rest, chest pain, or loss of consciousness are emergencies.
People with asthma, chronic obstructive pulmonary disease, or heart disease, along with young children, older adults, and anyone who is pregnant, have less reserve when an airway irritant is involved and should seek guidance sooner rather than later. This article is general information and is not a diagnosis.
The Investigations Still Open
Several agencies worked the scene. The city said the Minnesota Bureau of Criminal Apprehension responded to the crime scene and led the investigative response, and that the FBI assisted.
Accounts of how the suspected shooter died have not fully converged. The city initially said it was unknown. MPR News reported that officers exchanged gunfire with him, while CBS News Minnesota reported that sources told WCCO the death was a self-inflicted gunshot wound, an account other outlets later attributed to authorities. The Hennepin County Medical Examiner has not released a determination.
Peterson said police were familiar with the suspect but did not identify him publicly. FOX 9, CBS News, and the Star Tribune each named him as Carlton Neal Johnson II, 35, of Minneapolis, citing law enforcement sources and people with knowledge of the investigation. The Star Tribune reported that court records show Johnson was fighting eviction from the complex, and that the building has been the site of previous violent incidents.
Residents displaced from the building were directed to Central Lutheran Church at 333 South 12th Street, where the American Red Cross set up a shelter, and the Salvation Army provided food.
Readers should expect the substance question to be answered by the fire department or a hazardous materials assessment rather than by police, and that finding may arrive separately from the criminal investigation. Medical Daily will update this report when an agency identifies the substance or releases exposure guidance for residents.
Key Questions Answered
What is genuinely new here? City officials confirmed that four officers beyond the three injured in the shooting experienced adverse effects after exposure to an unknown airborne substance, and no agency has identified it.
Was the substance released on purpose? That is not established. Police have said only that officers encountered a haze and that they do not know what caused it.
How many people were hurt in total? Two people and the suspected shooter died. Three officers were injured, two by gunfire. Four more officers reported effects from the airborne substance; two were hurt in a squad car crash, and three other civilians were shot.
Are the injured officers expected to recover? Interim Chief Bill Peterson said all three injured officers were in stable condition and expected to make a full recovery. One was shot twice in the abdomen and another in the leg.
Should residents of the building be worried about what they breathed? There is no official exposure notice. Anyone who was inside and has respiratory symptoms should contact a clinician and describe where they were and for how long.
Who decides what the substance was? A hazardous materials assessment or fire department analysis would normally make that determination. No timeline has been announced.
What happens next? The Minnesota Bureau of Criminal Apprehension is leading the investigation, the medical examiner has not released cause of death findings, and police have not officially named the suspect.
