Solvent Exposure, Untested Ventilation and the Wrong Respirator
A printing and coating company in Lagos employs 60 people. Operators hand-wipe press rollers with a toluene/xylene-based solvent. A local exhaust ventilation (LEV) system was installed in 2019 but its airflow has never been measured. Staff wear disposable dust masks and thin cotton gloves. Noise in the press hall is 92–96 dBA over an eight-hour shift. Three workers report headaches and dizziness that improve at weekends, and one complains of numbness and tingling in the fingers of both hands. The 'medical' consists of a 10-minute GP check with no audiometry, no lung function and no biological monitoring; the company treats it as confidential and keeps no link to work exposure. Management believes the PPE and the annual check are enough, and has asked the HSE officer to confirm in writing that occupational health requirements are met.
1. The HSE officer is asked to confirm in writing that occupational health requirements are met. What is the correct response, and what gaps must be listed?
Read the worked answer
The officer cannot confirm compliance. Signing would be a false assurance and would remove the trigger for corrective action.
Gaps to list:
- No exposure monitoring: no personal solvent sampling, no noise dosimetry beyond a spot reading, no assessment against exposure limits.
- LEV never commissioned or tested. LEV requires commissioning, then thorough examination and testing at least every 14 months, with airflow or static pressure records; a system installed in 2019 with no records is of unknown effectiveness and may be making things worse by moving contaminated air around.
- Wrong RPE: a dust mask gives no protection against solvent vapour. Vapour requires a gas/vapour cartridge (A-type) and particulate combination, fit-tested.
- Wrong gloves: thin cotton gloves absorb and hold solvent against the skin; nitrile has poor resistance to aromatic solvents such as toluene and xylene, so it swells and permeates quickly.
- No health surveillance suitable for the hazards, and no health records linking results to exposure history - so deterioration cannot be detected.
Recommended wording of the reply: confirm that the hazards are recognised, state that compliance is not demonstrated, and set out a dated action plan with the exposure assessment first, because everything else depends on knowing the real exposure.
2. Specify the health surveillance that is actually required for these hazards.
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Noise (92–96 dBA, above the 85 dBA action value): baseline audiometry before placement, then periodic audiometry (typically annual while exposure continues), with a noise questionnaire; classify results against the baseline and act on any shift. Advise on hearing protection with fit checking, and reduce noise at source.
Solvents (toluene/xylene): pre-placement assessment including history of neurological, liver, kidney and skin problems; periodic biological monitoring - typically urinary hippuric acid or blood toluene for toluene, and methyl hippuric acid for xylene, sampled at the right time relative to the shift; liver function tests; a documented neurological examination covering peripheral sensation, since solvent exposure can cause peripheral neuropathy.
Skin: skin surveillance for irritant and allergic contact dermatitis on the hands and forearms, because hand-wiping guarantees skin contact.
General: results held in confidential individual health records, but with anonymised group summaries reported to management and linked to exposure data. The GP check is not a substitute for any of this - it is not hazard-specific, has no baseline, and cannot detect hearing or nerve damage early.
Also confirm the occupational health provider is competent to do the tests and to interpret them against exposure records.
3. Explain what the reported symptoms most likely indicate and what the HSE officer should do next.
Read the worked answer
Headaches and dizziness that improve at weekends are a classic pattern for acute solvent exposure at work - the weekend recovery is the diagnostic clue. Combined with an untested LEV, this points to inhalation exposure above a tolerable level, with the strongest suspicion falling on the LEV or on work practices (lid off solvent trays, wiping in an unventilated corner).
Numbness and tingling in both hands must not be dismissed. The differential includes peripheral neuropathy from solvent exposure and hand-arm vibration syndrome if the worker also uses vibrating tools; the pattern (both hands, symmetrical) leans towards a systemic cause, which makes it urgent rather than routine.
Actions: refer the worker to an occupational physician promptly and record the referral; do not move him to another solvent job as a 'solution' without medical advice. Treat the symptoms as a sentinel event that invalidates the existing risk assessment. Commission personal and static sampling, test the LEV, and put interim controls in place - enclosure, lids, reduced quantities of solvent at the bench, correct RPE and laminated-film or PVA gloves, no eating or smoking in the area. Check whether the condition is reportable as an occupational disease under the Factories Act and record it in the incident and ill-health register.