| Jones Bros Ruthin (Civil Engineering) Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Kevin Cahill Transport | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Kiely Bros Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Knauf Insulation Ltd | Knauf | building materials | Environmental Violation | 2020 | UK-NRW | £0 |
| LAM Smith and Sons Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Lewis Drainage Ltd (Robert Lewis) | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Lewis Homes (South Wales) Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Lodge Farm Biogas Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| M Jones Road Haulage Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| M&J Plant & Transport Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Maes Bach Holdings Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Metal Innovations UK | | | Environmental Violation | 2020 | UK-NRW | £0 |
| MJ Rubbish Removals Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Monger Caravan and Resorts Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Morris & Co (Handlers) Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Morrison Utility Services Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Mynachdy Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| NAT Group Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Norton's Plant Hire | | | Environmental Violation | 2020 | UK-NRW | £0 |
| P&M Waste | | | Environmental Violation | 2020 | UK-NRW | £0 |
| PB Leiner | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Perdez Pas Cyf | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Persimmon Homes Limited | Persimmon PLC | construction and engineering | Environmental Violation | 2020 | UK-NRW | £0 |
| Persimmon Homes Limited | Persimmon PLC | construction and engineering | Environmental Violation | 2020 | UK-NRW | £0 |
| Pontrilas Timber & Builders Merchants Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Poyston Farms Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Prichards Remediation Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Project Red Recycling Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Pryor & Rickett Silviculture | | | Environmental Violation | 2020 | UK-NRW | £0 |
| R E Cookson & Son | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Redrow Plc | Barratt Redrow | real estate | Environmental Violation | 2020 | UK-NRW | £0 |
| Redrow Plc | Barratt Redrow | real estate | Environmental Violation | 2020 | UK-NRW | £0 |
| Redrow Plc | Barratt Redrow | real estate | Environmental Violation | 2020 | UK-NRW | £0 |
| RFL Logistics Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Richie Builders Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Roadchef Ltd | Macquarie | financial services | Environmental Violation | 2020 | UK-NRW | £0 |
| SBS Salvage Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Sea Rivers Holiday Parks Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Shillibiers Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Sisters of St Joseph | | | Environmental Violation | 2020 | UK-NRW | £0 |
| South West Wood Products Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| South West Wood Products Ltd. | | | Environmental Violation | 2020 | UK-NRW | £0 |
| South West Wood Products Ltd. | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Stenor Environmental Services Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Stenor Environmental Services Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Stenor Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Straits Holiday Park Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Sundorne Products (Llanidloes) Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Swansea Airport Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Tata Steel UK Ltd | Tata Group | diversified | Environmental Violation | 2020 | UK-NRW | £0 |
| Tilhill Forestry Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Tom Prichard Contracting Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Tower Regeneration Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Tower Regeneration Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Tower Regeneration Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Tower Regeneration Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| V J Thomas & Son Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Valero Energy Ltd | Valero Energy | oil and gas | Environmental Violation | 2020 | UK-NRW | £0 |
| Valley Water Services Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Valleys Waste Services | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Veolia Energy and utility services | Veolia Group | waste management and environmental services | Environmental Violation | 2020 | UK-NRW | £0 |
| Walters Group UK | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Walters UK Limited | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Welsh Water Organic Energy (Cardiff) Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| Williams Homes (Bala) Ltd | | | Environmental Violation | 2020 | UK-NRW | £0 |
| A1 and A2 Limited | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Aberystwyth Park Lodge LTD | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Active Air Products Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| AD Recycling Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Allen's Caravans Estates Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Allport Metal Recycling Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Alun Griffiths (Contractors) Limited | CRH PLC | building materials | Environmental Violation | 2021 | UK-NRW | £0 |
| AMG Resources Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Ammanford Recycling Limited | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Anwyl Construction Company Limited | | | Environmental Violation | 2021 | UK-NRW | £0 |
| AQA Cardiff Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Asbestos (North Wales) Solutions Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Atlantic Plastic Recycling Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| AWD (Group) Ltd. | | | Environmental Violation | 2021 | UK-NRW | £0 |
| AWD (Group) Ltd. | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Bardsey Island Trust Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Bardsey Island Trust Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Bellway Homes Ltd (Wales) | Bellway PLC | construction and engineering | Environmental Violation | 2021 | UK-NRW | £0 |
| Bigft Construction Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Blaeneifed Farms Limited | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Bluestone Resorts Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Bron Afon Community Housing | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Cambrian Services Limited | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Cardigan Memorial Pool and Hall Trust | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Castle Cement Limited | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Chronos Pride International Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| CJS Electrical (Wales) Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Conway Forestry Limited | | | Environmental Violation | 2021 | UK-NRW | £0 |
| CPR Landscaping | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Crynfrynbychan Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Cuddy Demolition & Dismantling Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Cuddy Demolition & Dismantling Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| CWM Environmental Ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
| D Morgan PLC | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Dafen Service Station Limited | | | Environmental Violation | 2021 | UK-NRW | £0 |
| Dairy Partners (Cymru Wales) ltd | | | Environmental Violation | 2021 | UK-NRW | £0 |
