Solvent Vapour and Block-Cleaning Practice
A block-printing workshop employs six printers on two tables. Blocks are cleaned at the end of each shift in a 20 L open tray of kerosene, and the tray is placed near the printing table because the sink is across the room. There is no local exhaust ventilation; the only opening is a half-shuttered window. By 3 pm one printer reports headache and nausea, and another says the smell is strongest near the tray. Solvent-soaked rags are kept in an open bin, and an electrical socket is within 1 m of the tray. A pregnant worker is on the same shift. The supervisor proposes issuing masks and continuing, because the order is already late.
1. What immediate actions are required before work continues, and which control should not be relied on as the main fix?
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Work should stop in the affected area and the symptomatic printer moved to fresh air and assessed. The open tray should be closed and moved away from the printing table and electrical socket, and the rags placed in a closed metal container. The area should be ventilated immediately with the window fully open and, if available, a fan drawing air away from the workers. Masks alone are not the main fix: a nuisance mask will not reliably control kerosene vapour, and issuing masks without source control leaves the exposure in place. The main fix is to eliminate or contain the open solvent source and provide local exhaust at the cleaning point.
2. What engineering and work-practice controls would you put in place, and how would you verify they work?
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I would move cleaning to a designated area with a closable tray, local exhaust hood or extraction at the tray edge, and a fire-rated rag bin. Solvent should be dispensed in small amounts, not in an open 20 L tray, and the socket should be relocated away from the cleaning zone. Printers should be trained not to carry soaked rags to the table. Verification would include checking extraction airflow with a smoke test, recording symptoms and exposure complaints, and reviewing the cleaning procedure after one week. The pregnant worker should be moved away from the solvent area until controls are proven.
3. What records and follow-up would you require after the incident?
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Record the time, symptoms, persons affected, solvent used, quantity, ventilation condition and immediate actions. Report the incident through the unit's safety procedure and arrange a follow-up health check for the symptomatic worker. Review the cleaning method, storage and electrical placement, and set a date to install or repair extraction. The record should also show that the pregnant worker was reassigned and that controls were checked, not merely proposed.