Light, medium and heavy industry: what the classes mean for a factory in Klang

What each class means

The Department of Environment's Guidelines for Siting and Zoning of Industry and Residential Areas (second revised edition, October 2012) puts every industrial activity into one of five categories. The category drives how far the plant must be from homes, schools and other sensitive places.

Heavy industry (category 2) covers activities with high air pollution or odour, noise or vibration above safe limits, and large volumes of wastewater or scheduled waste that is hard to treat. Medium industry (category 3) has moderate pollution and fire or explosion risk, with scheduled waste that is mostly readily treated. Light industry (category 4) has no or very low pollution potential, no hazardous raw materials or products, and works at a small scale. High-risk installations (category 1) carry a very high risk of fire, explosion or radiation, and cottage industry (category 5) is home-based work with low energy use.

Examples from the DOE list

Appendix B of the DOE guideline lists activities by MSIC 2008 industry code with their category and buffer. A few examples relevant to Klang's factories:

• Blast furnaces and steel making: heavy (category 2), 600 m overall and 500 m primary buffer
• Steel rolling and finishing mills: heavy (category 2), 350 m and 300 m
• Structural metal products, tanks and containers: medium (category 3), 250 m and 200 m
• Plastic injection, extrusion and blow moulding: medium (category 3), 200 m and 150 m
• Industrial gases: medium (category 3), 300 m and 250 m
• Semiconductors and electronic components: light (category 4), 100 m and 80 m

Selangor's buffer rules today

Selangor's planning manual follows the DOE figures. The State Assembly was told in March 2023 that the fourth edition of the manual, approved in 2022, sets a 300 m buffer for heavy industry, measured from the industrial building wall to the residential building wall. That replaced the 500 m buffer in the 2010 edition.

You will still see 500 m for heavy and 250 m for medium industry quoted online. Those figures come from older or local documents, such as Selangor's 2010 manual and the Kuala Langat local plan, and are not the current Selangor standard. The local plan for the specific site and the DOE assessment decide the actual requirement.

What the land title does and does not tell you

Under section 52 of the National Land Code a title carries one of three land use categories: agriculture, building or industry. Section 117 limits industry land to industrial purposes such as factories, workshops, warehouses and docks for manufacturing, processing, storage and distribution. Light, medium and heavy are not statutory title categories.

Where a class applies, it shows up in the title's express conditions or in the local plan zoning, and the two do not always match. Selangor's State Assembly has acknowledged cases where local plan zoning did not follow the category and conditions on the title. Changing the category or the conditions needs an application to the state under section 124.

Approvals to check before you commit

A factory needs planning permission from the local council under section 19 of the Town and Country Planning Act 1976. The DOE treats a site suitability assessment as a basic requirement for any new industrial plant, and prescribed premises need written permission from the Director General.

Larger or more polluting projects need an Environmental Impact Assessment under the EIA Order 2015. Its schedules include, for example, chemical plants of 100 tonnes a day or more, industrial estate developments of 20 hectares or more, waste recovery and recycling plants, and iron and steel works above set capacities. If your process is borderline, ask for the DOE's preliminary site assessment before signing.

What this means in Klang

Pulau Indah Industrial Park's phase 1 is mostly occupied by heavy industries, and phase 2 is the Selangor Halal Hub (NST, 2020). In Telok Gong, Selangor has applied its Zero Discharge Policy, with 92 licences issued to premises there by April 2025, so operations that discharge waste face tighter controls. Klang's draft local plan 2035 proposes promoting low-impact, clean industry.

For most of the units on this site the stated class is medium industry. Ms Teh can check the title conditions and zoning of a shortlisted unit against your process before you commit, and point you to the council and DOE steps that apply.