Document 8RG2beK5yarDb3pJDE6qzaGqa
FILE NAME: Z//E
DATE: DOC#: /E
DOCUMENT DESCRIPTION:ZZ/ZDZ ZDh
INTERVENTION MEASURES ADOPTED IN ASBESTOS MILLING UNITS AT CUDOAPAH (ANDHRA PRADESH)
Participating Staff
Scientific Dr.S.K. Dave, A.D. Dr.L.J. Bhagia, R.O.
SUMMARY
Technical
Mr.S.H. Shah, Mr.J.B. Vyas,
Mr.K.B. Borse,
T.O.
L. T.-
L.A.
I intervention measures such as total or part.ial enclosure of
jaw crushers, mine owners
edge runner and vibrator to reduce the very high
were level
employed
by
the
in
the
milling
units
of asbestos
mines
at
of asbestos dust Pullivendalla. Cuddapah
( Andhra Pradesh). Similarly, suitable training and hea1N1 edt1ca-
tio11 prQGramrries in respect of the. usage of the
mask and protective clothes were organised for
respiratory
by
the
mine
owners.
In
the
semi-outomatic
the workers milling units, the
concentration of dust came down to below the TL\/ of 2 f!ml
in two processes. In other three milling units the dust concen-
(i
trations reduced to certain extent. The workers used respiratory
masks and overal s more requent y. All the protective measures
undertaken have been possible because of the frequent joint.
follow-up action by the Directorate General of Mines Safety
and the National Institute of Occupational Health.
BACKGR.Omm INFORMATION
. .
The Environmental-cum-Medical Survey was conducted in .the
asbestos ~inin~ and mifling units at Pullivendalla, Cuddapah _
(Andhra Pradesh) 1 The airborne dust concentration of asbestos
was found to be much below the Threshold Limit Value (TLV) 2 of 2
f/ml in ~i.ning units where wet drilling process was in use. How-
ever,
the
dust
.
concentrations in
l
various
other
sections
were
2
to
244 times higher than the TLV (Figs. 1 & 2). The overall preva-
lence of asbestosis was 11.5%. It was higher in milling workers
.,
2
( 21. 3%) as compared to the mining workers (3 .1% ). In-depth immunological studies revealed that alteration in the immunological pattern was correlated with exposure to asbestos dust and subsequent development of asbestosis 3 To reduce airborne dust concentration, engineering control measures including personal protection were adopted in three milling units. The present report examines whether the dust concentration of asbestos in workroom air reduced to below the TLV level.
OBJECTIVES
The objectives of the present study were as follows:
1.
To evaluate the efficacy of environmental engineering
measures adopted at various sites of the milling units;
2.
To examine the impact of health education on the use of
personal protective devices, and other health promotive
measures.
PLAN OF WOIUC
Intervention Measures
After the first phase of the study, several meetings were arranged with mine owners and mine managers in the presence of the Director General of Mines Safety, and the Director of Mines and Safety. All of them were clearly explained the existin~ levels of asbestos dust concentrations in the milling units and its possible adverse effects on health. They were also informed about the need to reduce the dust concentration level by appropriate environmental engineering control techniques, as well as use of personal protective devices (Fig.3).
3
Environmental Engineering Measures
A.
Three types of engineering control measures on vibrator
were adopted in three milling units:
(a)
Total enclosure of vibrator (Fig.4)
(b)
Total enclosure with a lid so that if there is a
mechanical defect it could be easily rectified
(Fig.S) and
(c)
Vibrators enclosed with jute bags.
In the first two types, one inlet was made to feed the raw material into the vibrator and one outlet for extracting the
processed material.
B.
On the jaw crusher or edge runner, iron
used with lids to feed the raw material (Fig.6).
enclosures
were
Measurement of Airborne Asbestos Fiber Concentration in Asbestos Milling Units:
The membrane filter method, as per the recommendation of the Bureau of Indian Standards (BIS-11450-1986) 4 was used for measurement of asbestos fiber in the work environment in the
~tiitng units before and after the adoption of environmental
engineering control measures.
R.ESULTS AND DISCUSSION Airborne fiber concentrations for. the various processes
in four asbestos mills before and after the installation of environmental engineering control measures are presented in Tables-1
to 3 and Fig.7. In Mill 'A' (Table-1), the reduction in fiber concentra-
tion was not conslderabl~, despite 'the fact'that the jaw crushers
4
'l'able-1
;
Average Asbestos Fiber Concentration Be~ore and ALter Initiation of Control Measures ill Mill 'A'*
Department N
Before
After
(Phase-I) N (Phase-II)
Conti:ol
Mean
Mean
Measures
Jaw Crusher Decorticator Vibrator (1)
7
24.14
4
(6.69-40.74)
S
28.82
3
(12. 49-42. 68)
7
222.45
4
(96.77-488.05)
Vibrator (2) 14
227.36
4
(150.0-283.SS)
Fiber Room
3
124 .13
4
(91.05-161.61)
18.33 (17 .51-19.16)
28.95 (5.55-55.79)
59.25 (6.80-102.03)
71.73 (14.76-129.13)
17.44 (S.61-34.65)
Lid
Nil
Partial enclosure & isolation
Partial enclosure & isolation
Slow movement in fiber collection
* Figures in parenthesis indicate Range.
N = Number of Samples.
had iron enclosures and the vibrators were covered with jute_ r
bags.
In Mill 'B', (Table-2) the fiber concentration reduced
considerably, as total enclosures were employed.
In Mill 'E', (Table-3), the vibrator was fully- --e-n-c-los-e-d--
,,.,.- --
->;"
and thereby it reduced the fiber concentration. An iron lid with
suction facilities was employed on dicorticator but- it did not
reduce the concentration significantly--:-because--the: lid on the . ~
5
'rable-2 Asbestos Fiber Concentration Before and After
Initiation or Control Measures in Hill 'B'*
Department N
Before
After
(Phase-I) N (Phase-II)
Control
Mean
Mean
Measures
Edge Runner Decorticator Vibrator Fiber Room
7
5.43
4
0.785
Enclosure
(0.97-11.61)
(0.47-1.59)
6
5.55
3
0.90
Isolation
(3.70-9.77)
(0.73-1.05)
4
14 .15
3
(lo. 11-23 .26)
3.53 (2.39-5.79)
Enclosure
4
35.25
3
15.00
Slow move-
(4.49-65.35)
(4.05-16.10) ment in
fiber col-
lection
* Figures in parenthesis indicate Range.
N = Number of Samples.
vibrator which was meant for correcting the mechanical defect was
frequently opened to pour the raw mate-rial. In addition, less powerful suction units were not to reauce .~ble ~~~----:-:-~--~---- the level.
except
In Mill 'F' (Fig.7), the processes were semi-automatic,
....-..~
---,--~~~ -- ~- "---------~~~ ...... ___ - ---
the f ibe_: __ f ee~ing syst_~Ill- wh!_ch was fully automatic. At the
fiber collection level also, the bags were enclosed and had out-
let for the processed mateFial. Sb, it reduced the fiber concen-
tration to below the TLV lev~l.
Use of Personal Protective Devices:
' ...
(A)
Two types of respiratory protective devices were provided
to the workers: one ordinary cloth type costing nearly Rs.3/- per
<'
6
Table-3
Asbestos Fiber Concentration Before and After Initiation of Control Measures in Mill 'B'*
Department N
Before
After
(Phase-I) N (Phase-II)
Control
Mean
Mean
Measures
Edge Runner 3
Decorticator 3
Vibrator
4
Hand
3
Screening
23.27
4
(9.15-42.88)
32.47
4
(18.45-58.34)
202.76
6
(123 .69-291.66)
57.85
4
(22.87-85.37)
19.16 (8.43-33.47)
26.20 (13 .55-47 .18)
12. 74 (0.86-44.63)
20.93 (5.00-33.16)
Nil
Lid & Suction Enclosure
Isolation & Slow movement
= * Figure= in parenthccis indi~te Rn~e.
N Number of Samples.
piece, and another ~1th fiber glass material (costing Rs.40/- per piece, with the cost of filter paper being Rs.4/- to - Rs.5/- per
piece). The. second one__ has been certified by the Central Labour
Institute ,___~ombay.
----------~~ -- - ------.
Al though the second one
-~- ~------
..,as much better than
the first, both of them could not help reduce the exposure level
of workers to the desired extent.
(B)
Two types of overalls were given: one without any button,
while the other front open with 6-7 buttons. The arrangement for
washing of these clothes was the responsibility of the mine
'I
owner. Though both the overalls were designed for females, as the
:1
e
n &
e-
per per our han vel
on, for ine
the
7
females were mostly employed in milling units, the males were also using these overalls while working.
Other Measures:
Canvassing against smoking habit was extensively fol-
lowed.
Th-e--
hazards of exposure to ------~------
as_best_os_ .J~_nd ... .
s_moking were put
---~---- ---- --
up in local langua~g-~e--~- o-n-- -~-t-h-e- ---walls of the milling units.
S~im.i-l-a-- -rl--y---,----t--h--e
dangers
--- .
of
al- -c--o. h--olis~ m--
were
also
e~ploinod
and advocated for de-addiction.
The need for establishment of 'Environmental-cum-Medical
Monitoring Cell' was stressed with the suggestion--that such ser-
,.._,~-,~.-.--
---- vices can either be hired from NIOH, CLI or the DGMS, or can be - -~----- -
created by joint action of all the mine owners. The Medical Cell
can carry out pre-employment and periodical medical examinations
of the workers.
The need for imparting training to the workers in the usage of respiratory masks and personal protective devices was emphasized.
The results of the study in details,. with names of the workers having asbestosis, have been commurticated to the DGMS, Dhanbad.
FUTURE PROGRAMME
Followup actions will be taken to reduce asbestos dust and fibre emission. It is planned to extend the study to opencast mines.
REFERENCES
1.
Annual Report, N.I.O.H., p.9, 1989-90.
8
2.
Encyclopaedia of Occupational Health and Safety (Third
Revised Edition), Asbestos, p. 185, 1983.
3.
Annual Report, N.I.O.H., p.B, 1990-91.
4.
BUreau of Indian Standards, IS 11450-1986. Method for
determination of Airborne Asbestos Fibre Concentration in
Work Environment by Light Microscopy, 1986.
~CT ION
antral