Managing Risks of Hazardous Chemicals

Identify → label → SDS → register → store/segregate → control. Five steps that map directly to the WHS Regulations Part 7.1.

Quick Take

• GHS 7 is mandatory for new labelling (since 1 Jan 2023).
• Register every hazardous chemical; manifest when Schedule 11 placard quantity exceeded.
• WES absolute duty (Reg 49) — must not be exceeded; not "reasonably practicable".
• Health monitoring mandatory for ongoing exposure to Schedule 14 chemicals.
• Records held 30 years (40 for asbestos).

1. Definition (Reg 5)

A hazardous chemical is a substance, mixture or article that satisfies GHS criteria — including:

• Health hazards: acute / chronic toxicity, carcinogenic, reproductive, sensitiser, target-organ.
• Physical hazards: flammable, oxidising, corrosive, reactive, explosive.

Most ADG dangerous goods are also hazardous chemicals, but the Code excludes Class 7 (radioactive), Division 6.2 (infectious), and most Class 9 (misc).

Generated chemicals count too — welding fume, sewer H₂S, RCS dust from cutting concrete.

2. PCBU duties (Reg 326–371)

1. Identify and assess — via label, SDS, generated chemicals.
2. Register — current list of every hazardous chemical on site, with SDS reference.
3. Manifest — for Schedule 11 chemicals exceeding placard quantity (notify primary emergency services).
4. Label and placard — correct container/pipework labels; placards on storage areas exceeding placard quantity.
5. SDS access — obtain at supply; readily available before first use; current within 5 years.
6. Storage and segregation — incompatible classes separated by distance or barriers.
7. Control measures — hierarchy: eliminate → substitute → isolate → engineering → admin → PPE.
8. Health monitoring (Reg 368) — Schedule 14 chemicals with significant ongoing risk.
9. Atmospheric monitoring (Reg 50) — for chemicals with WES; review controls if > 50% of standard.
10. Spill containment (Reg 357) — bunding, absorbents, compatibility checks.
11. Emergency plan — required if manifest quantity exceeded; share with primary emergency services.
12. Records — 30 years (40 for asbestos).

3. Register vs Manifest

![[managing_risks_of_hazardous_chemicals_img001.jpg|520]] Figure 1 — GHS pictograms with signal words. Both "Danger" and "Warning" are recognised; "Danger" denotes the more severe hazard.

Aspect	Register	Manifest
Scope	All hazardous chemicals	Schedule 11 only
Trigger	Mandatory always	Placard quantity exceeded
Purpose	PCBU & worker reference	Emergency services notification
Placard required	Only when placard qty exceeded	Yes

Example placard / manifest thresholds (Schedule 11)

Hazard class	Placard	Manifest
Flammable liquid Cat 1	50 L	500 L
Acute toxicity Cat 1	50 kg	500 kg
Oxidising liquid Cat 1	50 kg	500 kg

Once manifest quantity is exceeded: notify primary emergency services, provide site map + emergency plan, update on changes (Reg 352).

4. Storage & segregation

![[managing_risks_of_hazardous_chemicals_img002.jpg|520]] Figure 2 — Fire triangle. Removing fuel, oxygen, or ignition source breaks the triangle. Most chemical storage decisions trace back to this.

• Acids / bases — separate.
• Oxidisers — away from organics, solvents, flammables (per AS 4326).
• Flammable liquids — per AS 1940; vented cabinets; bunded.
• Compressed gases — upright, valve closed when unused, away from ignition, well ventilated, outdoor preferred.
• Containers stable, supported, fixed against dislodgement.
• Never store above incompatible material.
• Store dry unless SDS specifies moisture tolerance.
• Don't store where contamination of food / personal items / medication is possible.

5. Risk assessment (SDS-led)

![[managing_risks_of_hazardous_chemicals_img003.jpg|520]] Figure 3 — Engineering controls: enclosed booth, side-hood, grinding enclosure. Capture at the source beats general dilution every time.

For each chemical, consider:

1. Routes of entry — inhalation (primary for vapour/aerosol), skin / eye contact, ingestion.
2. SDS sections 2, 7, 8, 9, 10 — hazard, handling, exposure controls, properties, reactivity.
3. Exposure scenarios — frequency, duration, quantity, work process (spray, decant, heat, cut).
4. Foreseeable failures — power out (ventilation), spill onto incompatible plant.
5. Similarly Exposed Groups (SEGs) — if represent­able, assess group instead of every individual.

![[managing_risks_of_hazardous_chemicals_img004.jpg|520]] Figure 4 — Risk-assessment decision flow. Gather SDS + register + previous assessments → walk-through + consultation → assess routes / monitoring need → record outcome → review when triggers fire (new chemical, change of process, incident, HSR request).

6. Workplace Exposure Standards (WES) — Reg 49

Standard	Definition
TWA (8-hour)	Time-weighted average over 8-h day, 5-d week.
STEL	Short-term exposure limit; 15-min TWA.
Peak	Maximum airborne concentration over the shortest practicable period (≤ 15 min).

WES is absolute — must not be exceeded. The "reasonably practicable" qualifier doesn't apply.

Hazardous Chemical Information System (HCIS) — SWA database of WES values + guidance.

If results approach / exceed standard: review controls. For sensitisers (isocyanates), the "standard" is irrelevant — once sensitised, any re-exposure is a problem.

7. Atmospheric monitoring (Reg 50)

• Required for chemicals with a WES; baseline + periodic.
• Personal sampling (breathing zone) preferred over static.
• Trigger control review if > 50% of WES, or health monitoring indicates elevated exposure.
• Records 30 years retention.

8. Health monitoring (Reg 368)

Mandatory for ongoing significant exposure to Schedule 14 chemicals.

Schedule 14 includes:

• Acrylonitrile, benzene, isocyanates, lead, pentachlorophenol, RCS, asbestos, chromium VI, vinyl chloride, polycyclic aromatic hydrocarbons, cadmium, mercury, organotins.

Process:

• Registered medical practitioner with hazard-exposure experience; PCBU pays.
• Type per Schedule 14 (history, biological monitoring, lung function, X-ray as relevant).
• Worker informed pre-engagement.
• Confidential records ≥ 30 years (40 for asbestos).
• Adverse results → review controls + worker notification.
• Health monitoring does not replace controls; it verifies them.

9. Spill response & emergency plan

Spill containment (Reg 357)

• At point of use / handling / storage.
• Sized for the largest foreseeable spill without overflow.
• Compatible materials (no incompatible reactions).
• Bunding to prevent spread to groundwater / drains.
• Absorbents on hand; compatible types.

Emergency plan (Reg 351) — required if manifest quantity exceeded:

• Site map; chemical locations; alarm; evacuation routes.
• Isolation procedures; emergency-response team roles.
• Firefighting water retention (prevent environmental contamination).
• Hard copy on-site at all times; shared with emergency services.
• Tested / drilled regularly.

10. Records

Record	Retention
Register + SDS	Current + updates
Air monitoring	30 years
Health monitoring	30 years (40 for asbestos)
Training	Employment + reasonable period
Incidents	Annual review; investigate trends
Emergency plan + drills	Current; per emergency-services feedback

11. Common pitfalls / quick wins

Do

• Just-in-time ordering — reduce inventory & risk.
• Pre-mixed / diluted products where possible (eliminate worker mixing).
• Close containers immediately after use.
• Toolbox talks on SDS access and exposure routes.
• Annual control-effectiveness audit (inspection + monitoring trends).
• 2–3× annual emergency drills with local services.

Don't

• Rely on odour to detect a hazard (odour fatigue; not all chemicals smell).
• Use PPE as the primary control. It's the bottom of the hierarchy.
• Forget generated chemicals — welding fume, RCS, sewer gas.
• Leave decanted / waste containers unlabelled.
• Treat sensitisers like ordinary toxics — engineering control much more critical.

12. Cross-references

• Within §06: [[labelling_hazardous_chemicals]], [[safety_data_sheets]]
• See also: [[managing_risks_of_plant]], [[welding_processes]], [[spray_painting_and_powder_coating]] (generated chemicals + isocyanates)
• §07: [[respirable_crystalline_silica]], [[manage_and_control_asbestos]]
• Foundations: [[risk_management_process]]
• Glossary (PCBU, WES, SEG, manifest, placard): [[glossary_and_key_concepts]]

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Source: managing_risks_of_hazardous_chemicals.md (Safe Work Australia, model Code of Practice, CC-BY-NC 4.0). Last verified against SWA: 2026-04-27.