Thai Environmental Impact Assessment (EIA) Process

TL;DR

Environmental Impact Assessment (EIA) in Thailand is required for project types listed in MoNRE Notifications under the Enhancement and Conservation of National Environmental Quality Act B.E. 2535 (1992). Environmental + Health Impact Assessment (EHIA) applies to a sub-set of projects with serious health implications. Timelines: 6-18 months for EIA, 12-24 months for EHIA.

Project Categories

• Industrial estates and factories above size thresholds.
• Mining, quarrying.
• Petroleum.
• Power generation (above 10 MW for fossil).
• Dams, irrigation.
• Ports, airports.
• Hotels with 80+ rooms.
• Real-estate projects above 80 rai.
• Hospitals 30+ beds.

Process Steps

1. Screening (does project trigger EIA / EHIA list).
2. Scoping.
3. Baseline studies + impact prediction.
4. Mitigation measures + monitoring plan.
5. Public consultation (1-3 rounds depending on EIA vs EHIA).
6. ONEP (Office of Natural Resources and Environmental Policy and Planning) review.
7. Expert Committee deliberation.
8. Approval recorded; conditions attached.

EHIA Additional Layers

• Health Impact Assessment study by recognised consultant.
• Public consultation reach broader.
• Independent Organization review (Section 67 framework).

Common Mistakes

• Late discovery that project triggers EIA — restart at concept.
• Insufficient public-consultation reach.
• Skipping baseline season variability.
• Approving construction-design before EIA approval.

FAQs

1. Foreign-invested project considerations?

Same EIA rules; BOI promotion does not waive EIA.

Related Reading

• Business in Thailand Hub