1 The Maritime Safety Committee, at its
sixty-first session (7 to 11 December 1992), recognized that chronic
exposure to very low concentrations of benzene vapours in air, of the order
of a few parts per million, may cause leukaemia.
2 The Committee, at its sixty-sixth session (28 May
to 6 June 1996), desiring to protect the health of seafarers and to keep it
at a level similar to that of shore-based workers engaged in similar tasks,
approved MSC/Circ.752, by means of which it:
.1 approved minimum
safety standards for ships carrying mixtures the benzene content of which is
0.5 per cent or more; and
.2
invited Member Governments to apply the standards as soon as possible.
3 The Committee, at its seventy-seventh session (28 May to 6 June
2003), noting that the diseases caused by the aforementioned exposure were
still a source of great concern, agreed that MSC/Circ.752 was in need of
revision, in particular with respect to cargo operations, which pose the
largest risk of crew exposure to vapours from the products carried, and
approved Revised minimum safety standards for ships carrying liquids in bulk
containing benzene, as set out in the Annex, which also includes an example
of precautions to be given to the crew in connection with loading and gas
freeing operations.
4 Member
Governments are invited to apply the annexed Revised minimum safety
standards for ships carrying liquids in bulk containing benzene, including
precautions to be given to the crew in connection with loading and
gas-freeing operations appended thereto as soon as possible.
5 MSC/Circ.752 is hereby
revoked.
Annex Revised Minimum Safety Standards for Ships Carrying Liquids in Bulk Containing Benzene
Chronic exposure to very low concentrations of
benzene vapours in air may inter-alia cause leukaemia. In order to
protect the health of seafarers to the same level as that of shore-based
workers performing comparable tasks, measures should be taken for all
ships carrying bulk liquids containing benzene the content of which is
0.5% or more by mass. The following measures should be included as
indicated hereunder.
01 Information to the master
1.1 Prior to loading, the shipper should
provide both to the master and the Company, as defined in the ISM
Code, a Material Safety Data Sheet (MSDS) formatted in accordance
with resolution MSC.150(77), for cargoes containing benzene.
1.2 The cargoes that may
contain benzene are, for example, the cargoes listed in Appendix I
to Annex I to MARPOL 73/78, and the following bulk liquids:
.1 benzene and benzene mixtures;
.2 naphtha, varnish makers and paints
(75%); and
.3 white
spirit.
02 Information to the crew
2.1 It is the responsibility of the
master and the Company, that the crew is made aware of any work
situation concerning operations involving liquids in bulk containing
benzene that may impose a risk to their health. The crew should be
informed of relevant safety precautions prior to cargo operations.
2.2 The appendix
gives an example of precautions to be given to the crew in
connection with loading and gas-freeing operations.
03 Occupational exposure limits1
3.1 Crewmember exposure to airborne
concentrations of benzene vapours should be within the following
limits:
.1 a 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
.2 a Short Term Exposure
Limit (STEL) of five parts of benzene per million parts of air (5
ppm) over any 15-minute period.
1 Refer to the latest editions of the Tanker
Safety Guide (Chemicals) (ICS) and the International Safety
Guide for Oil Tankers & Chemicals (ISGOTT)( ICS, OCIMF and
IAPH). 04 Air quality monitoring
4.1 The airborne concentration of benzene
vapour should be measured by a trained2 and properly
protected person with an approved instrument, before any crew member
is authorized to work in a given area. Such measuring should be
continued whilst there is a risk of exposure to benzene vapours.
4.2 Alternative methods
giving the same degree of safety may also be considered acceptable.
2 See also paragraph 8 05 Personal protection
.1 Safety equipment
Ships carrying mixtures the benzene content of
which is 0.5% or more should carry safety equipment equivalent to
what is required in paragraph 14.2 of the IBC Code.
.2 Equipment for cargo operations on
deck
Whenever direct or
representative measurements indicate that the exposure limits are
exceeded during normal cargo handling operations,3 crew required to
work in the affected area should wear appropriate respiratory
equipment to be used in accordance with the manufacturers
instructions. Such equipment is indicated below,4 however the
crewmember may select a higher level of protection:
.1
Half face piece: in areas where the airborne concentration of
benzene vapours is expected to exceed 1 ppm but not more than 10
ppm;
.2 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;
.3
Air supplied respirators: in areas where the airborne concentration
of benzene vapours is expected to exceed 50 ppm, but not more than
100 ppm;
.4 Pressure
demand breathing apparatus and full protective clothing, resistant
to chemical attack5: in areas where the airborne concentration of
benzene is expected to be greater than 100 ppm; and
.5 Personal protective equipment: eye protection,
impervious gloves and a protective apron should be readily available
to crew members while sampling and gauging or when skin contact with
the cargo is likely.
3 The recommendations regarding air
purifying masks apply to operational uses of respiratory
equipment for the purposes of protection during normal cargo
handling operations and are not to be confused with those
provisions specified in 14.2.8 of the IBC Code.
4 There are existing
standards for respiratory protection equipment. These standards
include: American National Standard for Respiratory Protection
(ANSI Z88.2 . 1992); and the British Standard for Respiratory
Protection Devices, Valved Filtering Half Masks to Protect
Against Gases or Gases and Particles (BS EN 405: 1993).
5 Refer to SOLAS
regulation II/2-19 06 Maintenance of equipment for personal protection
The equipment for personal protection should be
maintained and replaced in accordance with the manufacturers’
instructions and in accordance with paragraph 14.2.6 of the IBC
Code. Maintenance records should be kept on board.
07 Entering into enclosed spaces
Explicit instructions6 from the
master or a responsible officer are required before any entry into
hazardous enclosed spaces. The hazards likely to be encountered
should be evaluated and it should be ensured that all precautionary
measures are taken. It should also be ensured that a responsible
person is in attendance during the period of entry and while the
space is occupied.
6 Refer to Recommendations for entering
enclosed spaces aboard ships, adopted by the Organization by
resolution A.864(20). 08 Training7
Crewmembers who might be exposed to benzene
vapours should be given proper training, which should include:
.1 the respiratory hazard and the effect on
the wearer if the respirator is not used properly;
.2 the engineering and administrative controls being
used and the need for respirators to provide protection;
.3 the reason for selecting a particular
type of respirator;
.4
the function, capabilities, and limitations of the selected
respirator; and
.5 the
method of donning the respirator and checking that it fits and is
operational.
7 Refer to the provisions of the
International Convention on Standards of Training Certification
and Watchkeeping for Seafarers, 1978, as amended , and in
particular to the .Mandatory minimum requirements for the
training and qualifications of masters, officers and ratings on
tankers. . regulation V/1 of the annex to that Convention . and
to section A-V/1 of the STCW Code (paragraphs 15 to
21). 09 Medical monitoring
Crewmembers potentially exposed to benzene
vapour inhalation should be submitted to a programme of regular
suitable medical checks on their health. The results of such checks
should be kept on record under normal confidential practices in the
medical profession.
10 Ship/shore connections
Prior to disconnecting, efficient and complete
draining* and purging of all pipes, hoses and hard arms used for
cargo handling should be ensured.
* Note: In accordance with MARPOL regulation
II/7(3), drainage back into the cargo tanks is not
allowed 11 Precautions during cargo operations
Cargo loading, tank cleaning and gas-freeing are
those procedures on board a tanker that expose the crew to the
largest risk of exposure to vapours from the products carried, both
in the accommodation and on open deck. It is, therefore, essential
during these operations that all:
.1 openings to the accommodation are closed or battened
down;
.2 ventilation in
the accommodation is either re-circulated or shut down; and
.3 work on deck follows
the provisions given in paragraph 5.2.
12 Controlled tank venting system
12.1 Vapours displaced from the tank
during loading, tank cleaning, tank breathing and gas-freeing should
be emitted through a controlled tank venting system complying with
either SOLAS regulation II-2/16.3.2, or paragraph 8.3.2 of the IBC
Code, or paragraph 2.14.2 of the BCH Code, as applicable.
12.2 Whenever a vapour
emission control system is available ashore, vapours displaced from
the tank during loading should be returned to that system (vapour
return).
13 Cargo measurements and sampling
All cargo related measurements (e.g., ullage,
temperature and sampling) should be carried out in a closed mode to
minimize the risk of exposing the crew and shore personnel to
harmful vapours. When this is not possible, personal protection
equipment should be worn.
14 Contaminated clothes
Working clothes should not be brought into the
accommodation. Therefore, whenever possible, all working clothes
should be removed and put in designated lockers prior to the crew
entering the accommodation. The IBC Code, chapter 14, and the BCH
Code, paragraph 3.16, deals extensively with personnel protection,
including storage of protective equipment and working
clothes.
Appendix Example of precautions to be given to the crew in connection with loading and gas-freeing operations
1 All doors leading from the outside to
the accommodation and to the engine room should be closed and kept
closed during these operations. Only one door on the windward
side/nearest to the cargo control room is to be used as an access..
2 All doors inside
the accommodation shall be kept closed during the operation.
3 The ventilation to the accommodation
shall be stopped/re-circulated and the fire flaps kept closed*.
4 Vapour concentrations
on deck shall be measured prior to any work being undertaken.
5 The crew working on
deck shall wear appropriate protective equipment.
6 Only work related to cargo handling
is allowed on deck.
7
Presence of personnel in the engine room shall be kept to a minimum
during these operations.
8 Bring no working clothes into the accommodation.
* To be modified to the actual ship.