NEBOSH Chemical and Biological Hazards 5

Question 1

What is the significance of the COSHH 'adequate control' standard for substances that do NOT have a WEL?

Accepted Answer

The employer must still reduce exposure to as low as is reasonably practicable, applying the principles of good practice set out in Schedule 2A of COSHH

Answer

For substances without a WEL, COSHH Regulation 7(7) requires exposure to be reduced to as low as is reasonably practicable. Schedule 2A sets out eight principles of good practice including: minimising emission, considering all routes of exposure, applying proportionate controls, providing PPE as a last resort, monitoring effectiveness, and informing/training employees.

Question 2

What precautions should be taken to prevent needlestick injuries that could transmit blood-borne viruses?

Accepted Answer

Use safety-engineered sharps devices, never recap needles, dispose of sharps immediately into approved containers, provide hepatitis B vaccination, and have a post-exposure procedure in place

Answer

Preventing needlestick injuries requires: using safety-engineered devices (retractable needles, blunted sutures), never recapping or bending used needles, immediate disposal into BS 7320-compliant sharps containers, providing hepatitis B vaccination for at-risk workers, having a post-exposure prophylaxis protocol, reporting all sharps injuries, and training in safe handling techniques.

Question 3

What is the absorption route of entry and what types of substances can enter the body through the skin?

Accepted Answer

Fat-soluble (lipophilic) substances such as organic solvents, pesticides, and some metals can pass through intact skin; damaged skin increases absorption of all substance types

Answer

The skin is semi-permeable and fat-soluble (lipophilic) substances can pass through intact skin into the bloodstream. Organic solvents (toluene, xylene), organophosphate pesticides, and some metals are readily absorbed. Cuts, abrasions, dermatitis, and chemical damage to the skin greatly increase absorption. Substances assigned a 'Sk' notation in EH40 can contribute significantly to overall exposure via the skin route.

Question 4

Under COSHH Regulation 9, how often must local exhaust ventilation (LEV) systems be examined and tested?

Accepted Answer

At least every 14 months, unless specific processes require more frequent examination

Answer

COSHH Regulation 9 requires LEV systems to be examined and tested at least every 14 months to ensure they remain effective. Some specific processes listed in Schedule 4 require more frequent examination (e.g., every 6 months for some processes such as blasting, dry grinding). Records of examinations must be kept for at least 5 years.

Question 5

What occupational exposure risks are associated with welding fumes, and how are they classified under COSHH?

Accepted Answer

Welding fumes are classified as a human carcinogen (causing lung cancer) and also cause metal fume fever, occupational asthma, and pneumonia — requiring COSHH assessment with LEV or RPE controls

Answer

In 2019, the HSE reclassified all welding fume as a human carcinogen based on IARC evidence. Exposure can cause lung cancer, metal fume fever (zinc/copper fumes), occupational asthma (chromium/nickel in stainless steel), pneumonia, and chronic lung disease. COSHH requires LEV or effective RPE for ALL welding, including mild steel, with adequate controls even for outdoor welding.

NEBOSH IGC Practice Test

NEBOSH IGC Practice Test

NEBOSH Chemical and Biological Hazards 5