NEBOSH Chemical Hazards

Question 1

What is the UN Globally Harmonized System (GHS) of Classification and Labelling of Chemicals?

Accepted Answer

An internationally standardized system for classifying chemical hazards and communicating them through standardized labels (pictograms, signal words, hazard and precautionary statements) and Safety Data Sheets

Answer

A Gulf-specific chemical safety system

Answer

A voluntary labelling system with no legal basis

Answer

A system only applicable to pharmaceutical products

Question 2

What are the main health effects of solvent exposure in the workplace?

Accepted Answer

Central nervous system depression (dizziness, headache, unconsciousness), liver and kidney damage from chronic exposure, dermatitis from skin defatting, and carcinogenicity for some solvents

Answer

Solvents only cause skin irritation

Answer

Solvents are non-toxic below visible vapour levels

Answer

Solvent exposure only affects workers over 50

Question 3

What is the correct control hierarchy for chemical exposures in the workplace?

Accepted Answer

Elimination, substitution with less hazardous substance, engineering controls (enclosure, LEV), administrative controls (reducing time, rotation), PPE — as last resort

Answer

PPE is the first and most important control

Answer

Administrative controls are more effective than engineering controls

Answer

Monitoring is the primary control for chemical hazards

Question 4

What is 'local exhaust ventilation' (LEV) and what is its purpose?

Accepted Answer

A system that captures airborne contaminants at or near the point of generation before they disperse into the general workplace air — more effective than general dilution ventilation

Answer

A general workplace ventilation system that dilutes contaminated air

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LEV is used only to control temperature

Answer

LEV is only required in chemical laboratories

Question 5

What are the GHS pictogram requirements for a substance classified as acutely toxic (category 1)?

Accepted Answer

Skull and crossbones (GHS06) with signal word 'Danger'

Answer

Exclamation mark (GHS07) with signal word 'Warning'

Answer

Flame (GHS02)

Answer

Health hazard (GHS08) for carcinogens

Question 6

What is 'reactive' or 'unstable' chemical hazard and how is it identified on SDS?

Accepted Answer

Chemicals that can detonate, deflagrate, or undergo violent decomposition — identified in Section 2 (hazard identification), Section 7 (handling/storage), and Section 10 (reactivity) of the SDS

Answer

Reactive chemicals only pose fire risk

Answer

Reactive chemicals are always corrosive

Answer

All chemicals are reactive under certain conditions — no specific SDS sections address this