Time to Clear the Air! — A Workers’ Pocket Guide to LEV INDG409

HSE INDG409 is a short worker-facing pocket guide explaining the basic checks employees should make when using Local Exhaust Ventilation systems.

The guidance explains that LEV should remove harmful dust, mist, fumes or gas from the workplace air, but only if it is suitable, properly installed, maintained, tested and used correctly. It also reminds workers to check indicators, signs of poor control, unusual noise or vibration, and whether the system has an in-date test label.

This resource is relevant to:

LEV Users

Workshop Operators

Laboratory Technicians

Supervisors

Health & Safety Professionals

Occupational Hygienists

Facilities Managers

Duty Holders

Source Document

View the HSE guidance here:

Source: Health and Safety Executive (HSE)
Document Type: Worker Pocket Guide
Status: Current
Last reviewed by LEVCentral: June 2026

LEVCentral Expert Commentary

INDG409 is a useful reminder that effective LEV control does not depend only on design, commissioning and statutory examination. Day-to-day users also play a critical role in ensuring the system continues to protect health.

The pocket guide is particularly valuable because it translates LEV management into simple user checks: is the system on, is the indicator showing correct performance, is the contaminant being captured, is the hood close enough, and are there signs of failure such as smells, dust deposits, noise or vibration.

For employers and duty holders, INDG409 supports the need for worker training, clear user instructions and routine pre-use checks. It also reinforces the importance of visible performance indicators and current test labels, so that users can recognise when LEV may not be providing adequate control.

This resource works well as a simple handout or toolbox-talk document for anyone using LEV in workshops, laboratories or production areas.