5 Checks Before Transferring Hazardous Chemicals

Transferring a hazardous chemical can release liquid, mist or vapour through an open container, a damaged hose, the wrong connection or an uncontrolled reaction. Safe transfer starts before the valve is opened. The method and controls must be based on the substance, quantity, equipment and conditions at your workplace.

Use the Safety Data Sheet to identify hazards, incompatibilities and handling requirements. Then carry out a task-specific COSHH assessment. HSE explains that an SDS supports the assessment but does not replace it.

1. Confirm the substance, quantity and transfer method

Match the product label to Section 1 of the current SDS. Check the supplier, product code, concentration and intended use. Review:

• Section 2 for health and physical hazards;
• Section 6 for spill precautions;
• Section 7 for handling and storage;
• Section 8 for exposure controls and PPE;
• Section 9 for relevant physical properties;
• Section 10 for stability, incompatibilities and conditions to avoid.

Define the transfer itself: the source and receiving containers, quantity, frequency, route, connection method and people who could be exposed. Include setup, sampling, disconnection, cleaning and maintenance. These stages often involve more direct contact than normal pumping.

If the SDS does not cover the concentration or process conditions you use, ask the supplier or a competent specialist before proceeding.

2. Use compatible, contained equipment

Closed transfer normally gives better control than open pouring because it reduces splashing, vapour release and direct handling. HSE's COSHH assessment guidance recommends enclosing processes and using closed transfer and handling systems where reasonably practicable.

Check that tanks, drums, hoses, pumps, seals, couplings and gaskets are compatible with the chemical and suitable for the pressure, temperature and flow. Use supplier data and the equipment manufacturer's limits rather than assumptions based on how the material looks.

Before each transfer:

• inspect hoses, seals, valves and couplings for wear, damage or contamination;
• confirm that the receiving container has enough capacity;
• identify the correct fill point and prevent cross-connection;
• secure containers and connections;
• provide secondary containment where a leak could spread;
• make sure vents and level controls are working;
• keep incompatible substances physically separated.

Every container must remain correctly labelled. Never rely on colour, smell or where a container normally sits to identify its contents.

3. Control exposure, fire and static risks

Consider every exposure route: inhalation, skin contact, eye contact and accidental ingestion. Prevent or reduce release at source. Depending on the assessment, this may require enclosure, local exhaust ventilation, splash guards, remote operation or restricted access.

PPE is the last line of defence. Select gloves, eye or face protection, protective clothing and respiratory protection from the SDS, exposure assessment and reliable compatibility data. “Chemical-resistant” is not a universal specification; breakthrough time and suitability vary by material and chemical.

If the product or vapour can ignite, assess the task under the Dangerous Substances and Explosive Atmospheres Regulations. Control ignition sources, ventilation and the formation of explosive atmospheres. Bonding and earthing may be needed to control static during the transfer of flammable liquids, but the arrangement must be designed for the equipment and process by a competent person.

HSE's principles of good control practice prioritise reducing emission, release and spread rather than relying on workers to avoid exposure after a substance has escaped.

4. Work within substance-specific operating limits

There is no single safe transfer temperature, pressure or flow rate for every hazardous chemical. Use the limits in the SDS, supplier's technical information, equipment specification and process risk assessment.

Temperature can affect viscosity, vapour generation, decomposition and pressure. Flow rate can affect splashing, foaming, static generation and the receiving container's ability to vent. Pressure can expose weak hoses, blocked vents or incorrect fittings. Monitor the parameters that matter for the substance and stop the process if they leave the approved range.

Do not improvise concentration tests or expose skin to check a product. Where concentration affects the risk or process, use an appropriate validated sampling and analytical method carried out by trained people.

5. Prepare for leaks, spills and abnormal conditions

Decide in advance how the transfer will be stopped and isolated. Emergency controls must be reachable without entering the release area. Workers should know:

• how to raise the alarm and stop the transfer;
• when to evacuate rather than attempt a clean-up;
• which spill kit or neutralising material is suitable;
• how to protect drains and the environment;
• where eyewash and emergency washing facilities are located;
• how contaminated PPE, absorbents and product will be disposed of;
• which first-aid and emergency contacts apply.

Test the arrangements and review them after leaks, near misses, equipment changes or changes to the product. Record inspection and maintenance requirements for safety-critical transfer equipment.

A practical transfer checklist

• The current SDS matches the exact product and concentration.
• The COSHH assessment covers the whole transfer task.
• The source, destination and connection points are positively identified.
• Equipment is compatible, inspected and within its operating limits.
• Containment, ventilation and ignition controls are ready.
• PPE is specific to the chemical and task.
• Emergency isolation, spill response and first-aid arrangements are in place.
• Trained workers know the stop conditions and do not work alone where the assessment requires assistance.

For the wider assessment process, see our step-by-step COSHH risk-assessment guide.