Viswa Lab, in its latest technical update, shared the information that few of its customers have identified 10 ppm of benzene in bunker tanks. Benzene is classified as a carcinogen, which increases the risk of cancer and other illnesses.
Identified level of Benzene
The customers have identified 10 ppm of benzene in bunker tanks when they were measuring the atmosphere for tank entry.
After resorting to extended ventilation, another measurement gave a value of 3 ppm of benzene.
Safety standards from IMO MSC
IMO Marine Safety Committee Publication MSC/Circ. 1095 “Revised Minimum Safety Standards for ships carrying liquids in bulk containing Benzene” states:
Crew member exposure to airborne concentrations of benzene vapours should be within the following limits:
- Time Weighted Average (TWA) of one part of benzene per million parts of air by volume (1 ppm), over an eight‐hour period, which covers the time a person is assumed to work in any 24‐hour period; and
- Short Term Exposure Limit (STEL) of five parts of benzene per million parts of air (5 ppm) over any 15‐minute period.
Points to be noted
The most important points in this document are:
Whenever direct or representative measurements indicate that the exposure limits are exceeded during normal cargo handling operations, crew required to work in the affected area should wear appropriate respiratory equipment to be used in accordance with the manufacturer’s instructions. Such equipment is indicated below, however the crew member may select a higher level of protection:
- Half face piece: in areas where the airborne concentration of benzene vapours is expected to exceed 1 ppm but not more than 10 ppm;
- Full face (filter) piece with cartridge: in areas where the airborne concentration of benzene vapours is expected to exceed 10 ppm but not more than 50 ppm;
- Air supplied respirators: in areas where the airborne concentration of benzene vapours is expected to exceed 50 ppm, but not more than 100 ppm;
- Pressure demand breathing apparatus and full protective clothing, resistant to chemical attack : in areas where the airborne concentration of benzene is expected to be greater than 100 ppm
Please check for the benzene content in the atmosphere before tank entry.
To assist with questions related to 2020 fuels Viswa has started and in‐house ‘Working Group’. You can reach us at wgfuels2020@theviswagroup.com
Please do not hesitate to contact us if you would like your VLSFO’s tested.
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Source: Viswa Group
