Professional Marine Training

TST E-Learning Recap Area

Module 36
Hexavalent Chromium

A structured TST infographic covering suspect exhaust insulation materials, testing process, risk assessment logic, upgraded PPE, contamination control, waste handling and Chief Engineer-level safe-task response.

Core HazardCr(VI)

Main Shipboard FocusExhaust & Turbocharger Areas

Control ThemeStop • Test • Contain

Oral Exam AngleRA + PPE + Safe Method

1 • Hazard Overview

What the examiner wants you to say first

Definition

Hexavalent chromium is the hazardous Cr(VI) form of chromium. In marine maintenance it is treated as a serious occupational health hazard when suspected on hot chromium-containing systems or associated residues.

Typical suspect locations

Exhaust manifolds, lagging and blankets, turbocharger casings, bellows, heat shields, hot flanges, stainless fasteners and disturbed residue/dust around these components.

Key oral phrase: “If I find suspicious yellow residue or contaminated dust around a hot exhaust system, I stop the job, control the area and treat it as a potential Cr(VI) exposure until the approved assessment/testing process is completed.”

2 • Health Risk

Why it matters

Respiratory exposure risk from disturbed dust/residue.
Skin and contamination-control concerns during handling.
Serious long-term occupational health implications.
Secondary exposure risk via tools, clothing and waste.

Exam tip: Never describe Cr(VI) as “just nuisance dust”.

3 • Exhaust Insulation Materials

What to say about lagging and insulation

Why insulation is relevant

Lagging, blankets, insulation boards and trapped dust can hold or spread suspect residue around hot chromium-containing components. Disturbing them during dismantling can create an exposure pathway.

Practical implication

Do not rip off insulation casually. Treat the task as a controlled contaminated-work activity if suspicion exists, and minimise dust generation throughout removal and handling.

Component / Material	Main concern
Lagging blankets / jackets	Can hold contaminated dust and release it during removal.
Insulation boards / packed lagging	May trap residues at hot joints, flanges and casings.
Heat shields and cladding	Can conceal suspect deposits until dismantled.
Residue around stainless fixings or hot surfaces	Needs assessment rather than assumptions from colour alone.

4 • Testing Process

Simple decision route

Recognise suspicion.
Yellow/yellow-green residue, dust or suspect contamination found during exhaust/lagging work.

Stop and contain.
Prevent further disturbance, control access and inform the responsible chain.

Assess and test.
Use the approved swab/screening method and task-specific risk assessment process.

Decide controls.
If positive, or still credibly suspect, treat as contaminated and escalate PPE/work controls.

Resume only under control.
Update permit/toolbox talk, use the correct method, then document and review.

Remember: a swab test is a screening/control tool. It does not replace a competent risk assessment or safe system of work.

5 • Risk Assessment Logic

Build the RA like a Chief Engineer

Hazard & task

What exactly is being dismantled? What residue, dust or insulation condition is present? How much disturbance is likely?

Persons at risk

Work party, standby personnel, nearby watchkeepers, cleaners, and anyone affected by contaminated tools, clothing or waste transfer.

Exposure routes

Inhalation, skin contamination, eye contact, and secondary spread from surfaces, PPE and handling routes.

Controls

Stop-work authority, containment, controlled ventilation, low-dust methods, HEPA vacuum where appropriate, hygiene and supervision.

PPE / RPE

Select fit-tested RPE, protective clothing, gloves and eye protection. Escalate if suspicion is high or testing is positive.

Emergency & review

First aid, eyewash, exposure reporting, medical advice route, waste control, records and lessons learned.

6 • PPE & Exposure Control

Baseline vs upgraded PPE

Control level	What it should include
Baseline controlled task	Fit-tested suitable RPE providing P3 particulate protection, gloves, eye protection and task-appropriate protective clothing under the approved procedure.
Upgraded PPE for positive/high suspicion	Enhanced RPE such as full-face protection with P3 filtration, disposable hooded coveralls, suitable gloves, contamination control for boots/tools and controlled doffing/decontamination.
Always required	Briefing, face-seal discipline, supervision, hygiene arrangements and clear contaminated/clean area control.

Good oral line: “Upgraded PPE means upgraded control of the whole task — not just wearing more items.”

7 • Waste, First Aid & Close-out

Finish the answer strongly

Cleaning: no dry sweeping or compressed-air blowdown.
Waste: contain, label and route through the controlled disposal process.
Decontamination: controlled doffing and washing to prevent secondary exposure.
Eye exposure: irrigate thoroughly and seek medical advice/report in line with procedure.
Management review: record findings, review RA/COSHH controls and update task guidance or PMS notes for future jobs.

Chief Engineer finish: “I would capture lessons learned and ensure future teams are better prepared for the same eventuality.”