Two Donegal sites have been included in the latest EPAs 2024 National Priority list.
The report out today identified Aurivo Consumer Foods Limited for discharges to water and Glenmore Biogas in Ballybofey for odour issues.
Water pollution and bad smells are the most common failures the EPA has found in breaches by waste and industrial facilities.
The environmental watchdog says food and drink, as well as waste facilities are most likely to breach compliance rules.
Meanwhile, complaints from the public around noise and bad smells have reduced by nearly half in the past three years.
Programme Manager at the EPA Office of Environmental Enforcement, Pamela McDonnell, says they focus on certain sites where they found problems in the past: