KOREATOWN (CBSLA)  —  One person is dead and three others injured in a case of possible carbon monoxide poisoning, police said.

The incident took place inside a 90-year-old apartment building at 920 S. Hobart in Koreatown.

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A hazardous-materials team arrived on scene.

The three injured were taken to a hospital, according to Stu Mundel reporting in in Sky9.

The entire building — 48 units — was evacuated as a precaution.

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Mundel reported that someone who lived inside the building died recently, and now investigators are trying to determine if that person might have also succumbed to carbon monoxide.

KCAL9’s Cristy Fajardo spoke to residents who were dealing with confusion and sorrow.

Neighbors told her that someone died in the building two days ago under mysterious circumstances.

Firefighters used sophisticated equipment to check for leaks.

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One neighbor said she believed the smell was coming from the elevator. The problem with carbon monoxide, however, is that that gas is tasteless and odorless.