An ammonia leak late Sunday night at the Scoular facility in Burlington prompted a six-hour shelter-in-place advisory before being fully resolved Monday, city officials said.

The incident began around 11:06 p.m. Sunday when Burlington Fire Department crews responded to an automated alarm at the agricultural storage and processing facility on South Anacortes Street. Firefighters detected a strong chemical odor and confirmed an ammonia leak from one of the plant’s industrial refrigeration units.

Residents within a half-mile radius were advised to shelter in place — closing doors and windows and shutting off HVAC systems — after an emergency alert was issued roughly six hours after the initial fire report. The facility houses an 8,600-pound ammonia tank, though officials have not said how much gas escaped.

Hazardous materials teams lifted the shelter order Monday morning, and South Anacortes Street has since reopened to normal traffic. No injuries were reported.

City officials said the Burlington Fire Department and HAZMAT teams are reviewing the incident response and communication timeline.