In recent years, Borneo has suffered from haze caused by forest fires in both Malaysia and Indonesia. In some years Borneo fires were so severe that they were also blamed to contribute to the Singapore haze.

During hazy conditions, air quality is poor. At peak times, healthy individuals experience irritation of the eyes and throat. People with chronic lung/heart disease and asthmatics may have worse conditions during haze.

Based on measurements of the concentration of toxic pollutants during haze on Borneo Brunei Shell Petroleum  concludes on their website that even if Brunei had several weeks of moderate Haze each year, the annual average exposure would be less than that resulting from living in a typical European city. Please see their Haze FAQ Section for further details.

It is difficult to forecast haze for specific areas, as it depends on the severity of forest fires, efforts undertaken to control them, rain, and wind direction. The Malaysian Ministry of Natural Resources and Environment publishes daily readings of the air pollution index .