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Environmental Impact Assessment (EIA) in Thailand

What is Environmental Impact Assessment?

Environmental Impact Assessment (EIA) is the assessment of the actual and potential environmental consequences or impacts of a plan, policy, program, or project proposals, prior to the decision to move forward with the proposed action.

What is the purpose of EIA?

The main purpose of an EIA in Thailand is to ensure that decision makers consider the environmental impacts when deciding whether or not to proceed with a project. This is to prevent environmental problems from major industrial projects in order to reach sustainable development goals. This procedure is significant in determining the type and level of effects an existing facility is having, or a proposed project would have, and identifying options to minimize damage on natural environment.

What happens if the project or activity may seriously affect the quality of the environment?

Projects and activities that may seriously affect the quality of the environment, natural resources and biological diversity are not permitted unless the environmental impact and health of the people in the communities have been studied and evaluated. Furthermore, they  must hold consultations with the public and organize the interested parties, and obtain the opinion of an independent organization before the operation of such project or activity.


In case of projects/activities that may negatively affect the living conditions of a nearby community and that require the approval of the Cabinet, authorization is more time-consuming and involves more stakeholders to ensure compliance with the law.

What is the procedure in conducting Environmental Impact Assessment ?

The Environmental Impact Evaluation Bureau (EIEB), under ONEP, is responsible for the administration of the EIA process. Large-scale ventures with significant environmental or surrounding habitat impact must forward Environmental Impact Assessment reports (EIA) to the Office of Natural Resources and Environmental Policy and Planning (ONEP), which then submits preliminary comments to the Expert Review Committee (ERC) for consideration.


ONEP then examines the EIA report within 15 days. In case the report is not correct or incomplete, ONEP sends the report back to the proponent. In case the report is correct or complete, ONEP provides preliminary comments on the EIA report within 30 days. The EIA report together with the preliminary comments is then proposed to the Expert Review Committee (ERC) which, in turn, considers the report for approval within 45 days.


After the approval of the report, ONEP gives recommendations to permitting agencies. If a project needs the approval from the Cabinet, then the ONEP summarizes the comments of the ERC and forwards them to the NEB and the Cabinet.


If the report is approved, the permitting agency shall therefore grant the permit to the project/activity with the inclusion of preconditions, such as mitigation measures and a monitoring program. Otherwise, the proponent must submit a revised report to the Committee. They shall then review the amended report within 30 days after date of receipt.


A licensed consulting firm registered with ONEP must prepare the EIA reports. The Minister of Natural Resources and Environment, with the approval of the National Environment Board (NEB), has the power to determine the type and size of projects or activities requiring an EIA.

What projects or activities require an EIA and EIA Approval?

  • Mining
  • Dams or Reservoir
  • Petroleum Development
  • Petroleum and oil transportation via pipeline
  • Industrial Estate or land development for residential or commercial purposes
  • Petrochemical Industry having Chemical Process
  • Oil Refinery
  • Natural Gas Separation or processing
  • Cement Production
  • Pulp Production
  • Pesticide Industry
  • Chemical Fertilizer Industry
  • Producing raw, white and refined sugar, glucose, dextrose, fructose
  • Iron or steel industry
  • Ore or Metal Smelting
  • Liquor, alcohol, including beer and wine production
  • Central waste treatment plant according to the factory act Thermal Power Plant
  • Expressway as defined by the Expressway and Rapid Transit Authority of Thailand Act or other projects alike
  • Infrastructure-highways, airports, new railway routes, ports for cruise and sport ships
  • Building located or utilized adjacent to river, sea, lake, beach, national and historical parks; Office, Commercial and Residential Buildings
  • Irrigation
  • Tourist resorts and recreational developments –resort facilities, hotels, and marinas