Chiribetsu Airfield

The closure was due to a combination of economic and operational factors. The primary reasons were:
1. **Operational Unreliability:** The airfield was located in an area prone to dense sea fog, resulting in a very low operational rate due to frequent flight cancellations.
2. **Inadequate Infrastructure:** It featured a short, unpaved (gravel) runway of approximately 800 meters, which could only accommodate small propeller aircraft (like the De Havilland Heron). This severely limited the type and scale of services it could offer.
3. **Economic Unsustainability:** Due to the frequent cancellations and limited capacity, the airport failed to attract sufficient traffic and operated at a significant financial loss for the city of Muroran, which owned and operated it. The opening of the larger, all-weather New Chitose Airport also diminished its strategic importance.

The site of the former airfield has been completely redeveloped. It is now occupied by the Muroran City Chiribetsu Water Purification Plant (室蘭市チリベツ浄水場). The long, flat plateau where the runway once existed is now home to water treatment facilities. All traces of the original airport infrastructure have been removed.

Officially named the Muroran Municipal Chiribetsu Airfield (室蘭市営チリベツ飛行場), it opened in July 1965. The airfield was established by the city of Muroran with the goal of boosting local tourism and industry by providing direct air access. It primarily handled sightseeing flights and irregular passenger services. The main airline to use the airfield was Japan Domestic Airlines (日本国内航空), a precursor to Japan Air System (JAS), which operated small aircraft. The airfield's short operational life of less than seven years serves as a case study in the challenges of operating small, regional airports in difficult meteorological conditions.

There are zero plans or prospects for reopening Chiribetsu Airfield. The land has been permanently repurposed for critical municipal infrastructure (the water purification plant), and the fundamental geographical and weather-related issues that led to its failure in the 1970s still exist. Regional air transportation needs are served by New Chitose Airport (CTS).