Document EqO1EZM74rnqKM6Y92wegoKmR
FILE NAME: Asbestos in India (IND)
DATE: 1991 DOC#: IND023
DOCUMENT DESCRIPTION: Report - Intervention Measures Adopted Asbestos Milling Units at Cuddapah
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INTERVENTION MEASURES ADOPTED IN ASBESTOS M ILLING UNITS AT CUDDAPAH (ANDHRA PRADESH)
Participating S ta ff
Scien tific
Dr.S.K. Dave, A.D. Dr.L.J. Bhagia, R.O.
Intervention
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SUMMARY
measures such n<t tmni
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Technical
Mr.S.H. Shah, Mr.J.B. Vgas, Mr.K.B. Borse,
T.O. L.T,
L.A,
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background inform ation
The Environmental-cum-Medical Survey was conducted in the asbestos raining and milling units at Pullivendalla, Cuddapah (Andhra Pradesh) . The airborne dust concentration of asbestos was found to be much below the Threshold Limit Value (TLV)2 of 2 f/l in mining units where wet drilling process was in use. How ever, the dust concentrations in various other sections were 2 to
244 times higher than the TLV1 (Figs. 1 g 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 immu
nological studies revealed that alteration in the immunological
pattern was correlated with exposure to asbestos dust and subse3
quent development of asbestosis . To reduce airborne dust concen
tration, engineering control measures including personal protec tion 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 WORK
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 existing 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 appro priate 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) (b)
,
Total enclosure of vibrator (Fig.4) Total enclosure with a lid so that if there is a mechanical defect it could be easily rectified
(Fig.5) 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 enclosures were
used with lids to feed the raw material (Fig.6).
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-1U50-1986) was used for measurement of asbestos fiber In the work environment In the mlillng units before and after the adoption of environmental engineering control measures.
RESULTS AND DISCUSSION Airborne fiber concentrations for the various processes
in four asbestos mills before and after the installation of envi ronmental engineering control measures are presented In Tables-1
to 3 and Fig.7.
In Mill 'A' (Table-1), the reduction in fiber concentre-
tlon was not considerable, despite the fact that the jaw crushers
4
Table-1
Average Asbestos Fiber Concentration Before and After Initiation of Control Measures in Mill 'A *
Department N
Before
After
(Phase-I)
N
(Phase-II)
Control
Mean
Mean
Measures
Jaw Crusher Decorticator Vibrator (1)
7
24.14
4
(6.69-40.74)
5
28.82
3
(12.49-42.68)
7
222.45
4
(96.77-488.05)
Vibrator (2) 14
227.36
4
(150.0-283.55)
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 (5.61-34.65)
Lid
Nil
Partial enclosure & isolation Partial enclosure & isolation Slow move ment In fiber col lection
* Figures in parenthesis indicate Range. N = Number of Samples.
had iron enclosures and the vibrators were covered with jute ,,
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
enclosed
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
Table-2
Asbestos Fiber Concentration Before and After
Initiation of Control Measures in Mill B**
Department N
Edge Runner 7
Decorticator 6
Vibrator
4
Fiber Room 4
Before (Phase-I)
N
Mean
5.43
4
(0.97-11.61)
5.55
3
(3.70-9.77)
14.15
3
(10.77-23.26)
35.25
3
(4.49-65.35)
After (Phase-II)
Mean
0.7S5 (0.47-1.59)
0.90 (0.73-1.05)
3.53 (2.39-5.79)
15.00 (4.05-16.10)
Control Measures
Enclosure
Isolation
Enclosure
Slow move ment in fiber col lection
* Figures in parenthesis indicate Range. N = Number of Samples.
vibrator which was meant for correcting the mechanical defect was frequentiy opened to pour the raw material. In addition, less powerful suction units were not^abTe~tcrireaude the level.
In Mill *F ' (Fig.7), the processes were semi-automatic, except the fiber feeding system which was fully automatic. At the fiber collection level also, the bags were enclosed and had out let for the processed material. So, it reduced the fiber concen tration to below the TLV level.
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 'E`*
Department N
Before
(Phase-I)
N
Mean
After (Phase-II)
Mean
Control 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 move ment
* Figures in parenthesis indicate Range. N = Number of Samples.
piece, and another with 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,-- Bombay. Although the second one was 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 owner. Though both the overalls were designed for females, as the
7
females were mostly employed in milling units, also using these overalls while working.
the males were
Other Measures:
Canvassing against smoking habit was extensively fol lowed. The hazards of exposure to asbestos^ and smoking were put up in local language on the walls of the milling units.
Similarly, the dangers of alcoholism were also explained and advocated for de-addiction.
The need for establishment of 'Environmental-cum-Medical
^ __
Monitoring Cell' was stressed with the suggestion that such ser
e
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
n &
can carry out pre-employment and periodical medical examinations
e-
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
per
workers having asbestosis, have been communicated to the DGMS,
per
Dhanbad.
our FUTURE PROGRAMME
han
vel
Followup actions will be taken to reduce asbestos dust
and fibre emission. It is planned to extend the study to open
cast mines. on,
for
REFERENCES
ine
7.
Annual Report, N.I.O.H., p.9, 1989-90.
the
8
Encyclopaedia of Occupational Health and Safety (Third Revised Edition), Asbestos, p. 185, 1983.
Annual Report, N.I.O.H., p.8, 1990-91. Bureau of Indian Standards, IS 11450-1986. Method for determination of Airborne Asbestos Fibre Concentration in Work Environment by Light Microscopy, 1986.
CTION ontrol
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