Document RJLLbaQB765Yvdb7DdL7eMQ8a

REVIEW REPORT Silica dust hazards in Vietnamese foundries Current situation and countermeasures Viet Nam General Confederation of Labour National Institute of Labour Protection ILO/FINNIDA Asian-Pacific Regional Programme on Occupational Safety and Health May 1999 1 Authors: Nguyen An Luong, Standing Vice President of the Viet Nam General Confederation of Labour (VGCL) Pham Van Hai, Head of Industrial Ventilation Department, National Institute of Labour Protection (NILP) Contributors: Nguyen Trinh Huong, NILP Nguyen Dieu Tran, NILP Tran Thanh Thuy, NILP Nguyen Huu Lap, Hanoi Mechanical Company An Thi Phuong, Electrical Engineering Company Sources: Hanoi Mechanical Company Electrical Engineering Company Hanoi Medical Centre Medical Centre of Vietnam Railway Medical Centre of Construction Ministry Trade Union of 20 provinces and cities: Hanoi, Haiphong, Quangninh, Cantho, Ho Chi Minh City, Caobang, Dongnai, Danang, Namdinh, Sonla, Thainguyen, Nghean, Thaibinh, Laocai, Vinhphuc, Phuyen, Hanam, Longan, and Tiengiang Ministries: Industry, National Defense, Transport, Construction, and Agriculture and Rural Development Translators: Nguyen Trinh Huong Nguyen Thang Loi Pham Van Hai 2 Table of Contents Acknowledgments............................................................................. 1. Introduction....................................................................................... 2. Overview: Current situation among Vietnamese foundries 2.1 Metal casting and its typical pollutants .......................................................... 2.2 NILP studies, 1981-1985 .................................................................................... 2.3 Results of initial foundry investigations, 1998 ............................................. 3. Pilot Survey in two Hanoi foundries......................................... 3.1 Hanoi Mechanical Company (HAMECO) ...................................................... 3.2 The Electrical Engineering Company............................................................ 3.3 NILP recommendations ....................................................................................... 4. Conclusions........................................................................................ References..................................................................................... Annexes ......................................................................................... Annex 1: Form1: Primary Survey form Annex 2: Form2: Personal Questionnaire Annex 3: Form3: survey for Evaluating Dust Prevention Practices 3 1. Introduction The national strategy on prevention of silicosis aims to reduce exposure to silica dust among foundry workers and others. Effective measures presuppose an investigation of the current situation in industry. Silicosis is a pulmonary disease caused by inhaling respirable silica dust. It is the leading occupational disease in Viet Nam. According to data provided by the Department of Preventive Medicine, foundries are among the five industrial sectors in which workers have the highest incidence of silicosis: 70.36 per cent (5). This report aims to overview the current situation in Vietnamese foundries, introduce NILP research results for 1981-1985 and 1998; conduct pilot surveys of two foundries in Hanoi; suggest measures to reduce exposure to silica dust; and prepare a survey form for evaluating dust-prevention practices. Methodology questionnaires and interview study of previous research and data field study expert counselling Questionnaires a) Form1: Primary Survey form (SeeAnnex1) The primary nation-wide survey seeks to clarify for each city, province, and industry the following issues: number of foundries capacity of each foundry number of male and female employees number of silicosis cases number of occupational accidents current situation of technology, dust-reduction measures, and plans for the future Form 1 comes with two letters enclosed. One of them, from the standing vice president of the VGCL requires the collaboration of trade unions in cities, provinces, and industries. The other letter, from the NILP, explains how to answer the questionnaire and provides a contact address. 4 b) Form2: Personal Questionnaire (see Annex 2) Fifty of these questionnaires, designed to investigate working conditions, are distributed to each pilot foundry. The questionnaire aims to determine worker awareness of occupational safety and health (OSH), working conditions, silicosis, and preventive measures already in place. Form 2 was distributed directly to employees in two workships in Hanoi. Respondents were selected in a way that cast light on the various stages in the foundry process. Interview The direct interview is intended for safety officers, health officers, production managers, and the company directorate. Study of previous research and data A study was carried out on the following research and data: results of the state level projects conducted on silicosis foundry workers by the NILP during 1981 -1985 data regarding health, X-rays, and silicosis cases at two pilot enterprises for the period 1995-1998 company policies on OSH Field studies The following field studies were carried out: visual observation of technological processes and dust-prevention measures measurement of dust concentrations at various stages of production photographing specific operations laboratory analysis of dust samples Expert consultations Experts were consulted on the following issues: classifying degrees of severity in silicosis cases appropriate technology dust-prevention measures compiling survey forms 5 2. Overview: Current situation in Vietnamese foundries 2.1 Metal casting and its typical pollutants Metal casting is a process in which molten metal is poured into heat-resistant moulds. The basic principles of foundry technology have changed little in thousands of years. However, in industrially developed countries, many stages of the process have been mechanized or automated. In Viet Nam, foundry technology is by those standards obsolescent. Manual labour is still the rule, except where mechanized equipment is necessary. In addition, lack of or ineffective dust-control systems makes the working environment more hazardous. A brief description of the main foundry processes helps to establish the background to the current situation in Vietnamese foundries: Making a pattern of the desired article. Traditional wooden patterns remain the most common practice in Viet Nam. Pollutants include noise and wood dust from sawing and cutting machines. Making the mould and core and assembling the mould. There are two types of moulds: A "green" sand mould is made from silica sand, coal dust, clay, and organic binder. Green sand mould does not need drying. A dry mould, on the other hand, uses silica sand, clay, and water, painted with molasses and coal dust. The mould is then dried in an oven. Moulds are also distinguished by their form: on a sand floor or in a flask. Normally, casting on a sand floor is used for small articles, flasks for casting large ones. The danger of dust in the moulding process is minimal because the moulding sand is usually damp - except where sand mixer and muller, which are often significant sources of dust, are involved. Melting the metal. Iron melting is often done in a cupola. Scraps of iron, coke, and limestone, charged in layers, provide the raw material. A fan blows air into the cupola. Melting, at temperatures of 1200-12500C, requires 5 to 6 hours, depending on the capacity of the cupola. The molten iron is poured into ladles which, in turn, are used to pour the material into moulds. Pollutants include fumes, toxic gases, dust, and noise. Where induction furnaces are substituted for cupolas, there is less pollution. Steel melting furnaces employ an electric arc. Raw materials include steel bars, steel scrap, and additives. The temperature in the furnace can be adjusted by changing the elevation of the electrode. When steel is melted at temperatures of 1400-1450C, ingots are often added to adjust the carbon component in the steel. Aside from that, the process is similar to that of iron casting. Pollutants include fumes, toxic gases, dust, and noise. Less dust is generated in steel melting than in iron melting. Very often, however, melting furnaces without hoods emit dust and fumes inside the station, polluting upper zones such as that where crane cabins are located. 6  Cooling the casting and removing the mould. After cooling, the casting is removed, or "shaken out" of, the mould either manually or using a vibrating grid. The sand is collected, treated, and either re-used or dumped. This workstation is especially hazardous because in contact with hot metal sand changes its crystal structure, becoming more toxic. Exposed to high levels of dust and work intensity, workers at this station are at high risk of silicosis. Cleaning the casting. After removal from the mould, the casting is cleaned. Cleaning includes removal of burnt-on moulding sand, cutting away surplus metal, and surface finishing. Cleaning tools include pneumatic hand chisels, grinders, and welding or cutting torches. This process is a major source of dust and noise. Advanced technology uses steel shot-blasting or, better, water or water and sand shot-blasting in an enclosed cabinet, eliminating exposure to hazardous silica dust. 2.2 NILP studies, 1981-1985. From 1981 till 1985, Thai Quang Hoe and others from the NILP carried out State Research Project #58.01.02.02: "Study and application of technical measures to protect workers from silicosis in foundries in Viet Nam". The project selected Tran Hung Dao, a manufacturer in Hanoi, together with eight other foundries throughout the country as pilot sites for study. Dust concentration measurements were conducted mainly at the Tran Hung Dao mechanical company. Silicosis and general health studies were carried out on a total 1,520 workers. Some study results follow. Environmental measurements Table 1: Dust concentrations (mg/m3) in foundry workstations Work station Materials mixinq Makinq moulds Metal-meltinq furnace Removing castings Cleaning castings by hand Crane cabin Handling used sand Source: NI LP,1982 Total dust concentration (mg/m3) 14.8-41.1 7.8-27.8 1-7.9 7.4-14.8 7.9 5.3 22-32 Portion (%) of respiratory dust (2-5 um ) 1-8.6 25 14.3 25 25.8 - 14.2 Percentage (%) of free silica (SiO2) 80 24 24 64 32 40 40 7 Comments The percentage of free silica (SiO2) in foundry dust fluctuates between 24 and 80 per cent, depending on the process stage. Average proportions of free silica are highest (80 per cent) at the materials-mixing stage, while they are lowest (24 per cent) in the mould-making and furnace stages. During removal of castings, it averages 64 per cent. Dust concentrations are highest (22-32 mg/m3) during sand handling, while they are lowest (1 -7.9 mg/m3) during the melting and pouring of iron into the mould. Dust concentrations (7.4-1 4.8mg/m3) are relatively moderate at the mould- and core-removing stages, but they are especially dangerous because they contain a high percentage of free silica. The average proportion of respiratory dust is highest (< 5 pm) during the cleaning of castings (25.8 per cent) and lowest (1-8.6 per cent) during materials mixing. These studies indicate that air in foundries is polluted by dust with a high percentage of free silica and a very high portion of respiratory particles. Removal of castings from moulds and cores and cleaning of castings are particularly dangerous stages in the foundry process. This is the main reason for the high rate of silicosis among foundry workers. Results of silicosis studies From 1982 till 1985, NILP researchers selected 1,520 workers for medical examinations, including chest X-rays, from the following factories: Hanoi Mechanical Company, Foundry Company Number 1 (Ho Chi Minh City), Ha Son Binh Mechanical Company (Hatay Province), Quang Trung Mechanical Company (Hanoi), Mai Dong Mechanical Company (Hanoi), Instrumental Company Number 1 (Hanoi), and Ha Nam Ninh Mechanical Company (Hanam Province). Among the 1,520 workers examined (831 men and 689 women), 608 workers were found to be suffering from silicosis (370 men and 238 women). Percentage of silicosis cases is 40 per cent (608/1,520) of which men occupied 24.3 per cent (370/1,520) and women 15.7 per cent (238/1,520). Men suffered 60.8 per cent and women 39.2 per cent of the 608 silicosis cases. 8 Silicosis was distributed in terms of degree of severity as follows: Table 2 Silicosis cases, distributed by degree of severity Silicosis, degree of Number of silicosis Percentage severity 1/Op cases 180 (%) 29.6 1p 1/2p 2p 150 24.4 98 16.1 86 14.2 2/3p 3p 1m 76 12.5 14 2.3 11 1.81 2m A T otal 12 1.97 4 0.16 608 100.0 Note: These categories are based on ILO International Classification of Radiographs of Pneumoconioses (1980). Severity is described as profusion from 0/- to 3/+, based on assessment of the concentration opacities by comparison with the standard radiographs. P,m and A define the greatest diameter of the predominant opacities Table 3 Silicosis cases, distributed by working history (in years) Working years <5 Examined 286 Silicosis cases 44 Percentage % Compared Compared with examined with sufferers 15.4 7.2 6-10 453 113 24.9 18.6 11-15 430 240 55.8 39.5 16-20 187 95 50.8 15.6 21-25 82 55 67 9.0 26-30 53 40 75.5 6.6 >30 29 21 72.4 3.5 Total 1 520 608 100 9 Table 4 Silicosis cases, distributed by skill rank Skill rank Numbers of examined workers Numbers of silicosis cases Percentage % Compared with numbers of silicosis cases Compared with numbers of examined same skill II 249 33 5.4 13.3 III 244 168 27.6 68.9 IV 713 263 43.3 36.9 V 206 94 15.5 45.6 VI 98 42 6.9 42.9 VII 10 8 1.3 80 Total 1 520 608 100 - Note: Skill rank is a common occupational classification in Viet Nam. Ranks in the foundry vary according to the job performed. For example, in the moulding stage a worker of the 2nd rank can make simple moulds, while workers of higher make more complicated shapes. Table 5 Development of silicosis among 122 cases observed from 1980 to 1984 Year Number of silicosis cases 1980 1984 122 122 1p 100 90 Silicosis degree p 2p 3p 19 1 13 0 Total 120 103 m 1m 2m 11 11 7 A A 0 1 Note: P, m, and n are abbreviations for Latin words. P stands for puntiformis; m stands for micro nodularis; and n stands for nodulavis. The figures indicate the degree of silicosis classified according to ILO/WHO Classification. Comments The studies involved a significant number of workers in various foundries ranging in size from medium to large scale, and the following remarks can be made with some confidence: A high proportion of foundry workers (40 per cent) suffer from silicosis. This represents a clear warning regarding employee health. Although the percentage of sufferers is high, the illness does not develop much from one degree to another. Few people suffered from silicosis of m and A degrees, and none were at the n, B, or C stages. This suggests worker health was generally bad because they had to stop working when the illness had not yet 10 developed to a more severe stage. They were released from the production line because they were unable to work. The incidence of silicosis is related to skill ranking in the same way that it is to number of working years. That means the higher the skill rank, the higher the incidence of silicosis. And it means that very few skilled workers are found on the production line in foundries. Production-line workers are mainly of rank II, III, IV (see Table 4). Among 122 afflicted workers, after 3-4 years, only 18 per cent of the cases had developed a more severe form of the illness. This rate is not very high. Nevertheless, prevention measures should be considered. 2.3 Results of initial foundry investigations in 1998 Comprehensive statistic data about Vietnamese foundries has never before been available. This study means to provide, among other information, the following: number of foundries number of workers working in foundries number of workers suffering from silicosis number of work-related accidents in foundries technological state of foundries, including dust-abatement measures In order to collect information, the Project has used as collaborators organizations such as the Trade Unions Net, which is active in provinces, industries, health departments, and health centres. However, given limited time and its wide range of concern, the Project has not received as many reports as expected. So far, only 20 provinces and 61 cities have reported, and 6 provinces reported not having a foundry. All relevant ministries - the Industry, Construction, Transport, Agriculture and Rural Development, and National Defense ministries - have submitted good reports. Although only 30 per cent of provinces and cities and some ministries reported, it was in these areas that most foundries and foundry workers were concentrated. Therefore, the available data. presented in Table 6, can serve as the basis for analyzing foundries in Viet Nam. Distribution of foundries and workforce by province and industry The Agriculture and Rural Development Ministry led the list, with 15.7 per cent equals 13 of the 83 foundries. The National Defense and Industry ministries accounted for 12 out of 83, or 14.5 per cent. The Transport Ministry accounted for 8 of the total, or 9.6 per cent, while, with 6 out of 83, Hanoi accounted for 7.2 per cent. Provinces such as Can Tho, Nam Dinh, Son La, Nghe An and Thai Binh had only one foundry each, accounting for 1.2 per cent each. 11 However, simple foundry numbers did not accurately represent the magnitude of the industry in each case. Production capacity and worker numbers were also important. Among a total of 4,028 workers, the Industry Ministry stood at the top of the list, with 32 per cent. The Defense Ministry was next with 11.9 per cent, followed by Quang Ninh with 8.4 per cent, Dong Nai with 7.9 per cent, Hai Phong with 7.8 per cent, Hanoi with 6.6 per cent, and the remaining provinces and industries together accounting for 25.4 per cent. No child labourers were found in state-owned foundries. Incidence of silicosis Statistic data indicate that, among a total of 4,028 workers, 383 (31 7 male and 66 female) suffered from silicosis. In other words, 9.5 per cent of the total were victims, 7.9 per cent of the total being male and 1.6 per cent female. Of the 383 actual sufferers, 82.8 per cent were male and 17.2 per cent were female. The Industry Ministry had the greatest number of sufferers, with 1 71 out of the total 383, or 44.6 per cent. The National Defense Ministry was next, with 62, or 16.2 per cent; followed by Hanoi with 47, or 12.3 per cent; Quang Ninh with 29, or 7.6 per cent; the Construction Ministry with 22, or 5.7 per cent; the Transport Ministry with 1 7, or 4.4 per cent; Hai Phong with 13, or 3.4 per cent; and the remaining provinces and industries with only an insignificant portion. (Figure 1) Figure 1 . Percentage of silicosis-sufferers distributed by provinces and industries 12 Some provinces with large numbers of foundry workers have yet to identify silicosis victims. But any conclusions regarding incidence of silicosis, in these cases, must await investigation of local examination and X-ray procedures. For example, the 1998 figures are only about one-quarter those reported in 1985, with reported female victims 9.8 times fewer. (See Table 2.) The following factors may be responsible for the apparent change in the incidence of silicosis: The 1985 data came from high-capacity foundries employing significant numbers of workers. These workers had all received medical examinations including chest X-rays. Where silicosis existed in this sample population, it was identified. The 1998 data, on the other hand, are merely statistics reported by provinces and industries. In many cases, workers exposed to silica dust had not been given medical exams and chest X-rays. Some technological improvements have been made, however, and dust concentrations at the mould-making stage, for example, have been much reduced. This would also help to explain the figures concerning females, since a disproportionate number of women are employed in mould making. 45 40 8^ 35 CD 30 03 CO 25 cJ-i CD 20 O i_ CD 15 CL 10 5 0 40 9.5 Total 24.3 7.9 Males 15.7 16 i____ Females Figure2. Comparison of silicosis-suffering percentages in 1985 and 1998 1985 1998 Work-related accidents Given insufficient statistic data, it is difficult to evaluate work-related accidents. However, it is obvious that accident rates remain high in provinces such as Da Nang (19), Can Tho (16), and Cao Bang (12). Common foundry accidents include burns from hot metal and pinching from crane chains. 13 Recommendations: Methods of information collection and assessment The collection of information on foundries should continue, using Form 3 (See Annex 3) to update the existing data. The Presidium of the VGCL requires that trade unions in cities, provinces and industries with foundries be given the responsibility for administering Form 3 and sending the collected data to the NILP every year before the end of November. The NILP needs financial support from the VGCL, with about 20 million VND required to pay those who fill in Form 3 and send the data to the NILP for assessment. The results of data collection and assessment should be disseminated to national taskforces on the elimination of silicosis. 14 Table 6. Statistics on Vietnamese foundries (1998) Number Capacity Provinces, cities, and N0 industries of in tonnes/ foundries year Workforce Total Male Female Number of silicosis cases Total Male Female 1 Hanoi 6 3 978 266 175 91 47 2 Quanq Ninh 4 4 050 340 232 108 29 3 Can Tho 1 60 000 111 110 01 0 4 Ho Chi Minh City 4 505 42 40 02 9 5 Cao Bang 3 14 100 244 179 65 0 6 Dong Nai 5 91 068 317 278 39 6 7 Da Nang 2 8 048 124 124 03 8 Namdinh 1 300 34 20 14 2 9 Son La 1 30 6 5 12 10 Hai Phong 3 12 982 313 251 62 13 11 Nghe An 1 80 38 33 50 12 Thai Binh 1 500 20 17 30 Ministries: 13 Agriculture 13 42 36 60 14 Industry 12 187105 1 290 1087 203 171 15 Construction 6 226 166 60 22 16 Transport 8 135 87 48 17 17 National Defence 12 4 539 480 335 145 62 Total 83 4 028 3 175 853 383 Note: NR= not reported - Provinces: PhL yLn, Hl nam, LLo cai, VLnh phLc, Long an, TiLn giang: foundries do not exist - 6 foundries in Thainguyen, but listed under the Ministry of Industry 37 28 0 9 0 4 3 2 2 7 0 0 0 142 22 13 48 317 10 1 0 0 0 2 0 0 0 6 0 0 0 29 0 4 14 66 Number of compensated cases 9 29 0 0 0 1 3 2 0 6 0 0 0 42 1 8 14 115 Number of work-related accidents 9 5 16 NR 12 8 19 NR NR 6 3 NR NR 68 NR NR 6 15 3. Pilot survey in two Hanoi foundries 3.1 Hanoi Mechanical Company (HAMECO) HAMECO, established in 1958, is situated in Nguyen Trai Road, Thanh Xuan District, Hanoi City. The first objective in constructing this factory was to establish a modern mechanical plant as the flagship of the machine tool industry. At the time, the factory was the largest in Southeast Asia. Company products include machines tool such as cutting, planing, and drilling equipment. Currently, HAMECO ranks first in manufacturing equipment for the sugar industry. The foundry, with a designed capacity of 8,000 tonnes of cast-iron and steel per year, is the most important part of the production process. Now, because of a slump in the manufacturing sector, foundry capacity has been reduced to 4,000 tonnes/year. Production process HAMECO operates two foundries: Steel foundry Steel scraps and ingots are melted in two electric-arc furnaces with capacities of 1.5 tonnes and 3 tonnes per batch, respectively. The molten steel is poured into ladles, which are then transported by crane to "green sand" moulds, where the molten metal is poured. Castings may be as large as 4,000 kilograms. Cooling time before removing the moulds is four days for large articles and one day for small ones. Mould removal employs vibrating grids, while casts are cleaned by hand. Cast-iron foundry The cast-iron is melted in 250-kilogram batches in induction-type furnaces. With castings weighing more than 250 kilograms, the iron is melted in an electric-arc furnace and transported by crane from the steel workshop. Both green sand and dry moulds are used. Moulds are shaken out and casts are cleaned by hand. The used sand is screened and reused. Working environment All foundry processes - mould making, metal melting, mould removal, cast cleaning, mould drying, etc. - generate dust. Most of the equipment was provided by the former Soviet Union, and, after 40 years of use (1958-1998), much of it is in poor repair, especially the ventilation and exhaust systems. Obsolete technology together with ailing dust and fume control systems exacerbate any hazardous conditions. Given the nature of foundry production, all processes are on line and unpartitioned one from the other (excluding a drum-shaped cleaning machine situated in a separate room), so dust 16 spreads easily from one work area to another. Consequently all areas of the foundry, including the manager's office, are polluted. Table 7: Silica dust concentrations in different sampling places. Sampling place N0 1 Melting steel furnace: - 4 m from furnace door (fixed sample) - Personal sampling 2 In crane cabin 3 Mould-removing (personal sample carrying during clean-up and preliminary cleaning of casting) 4 Cleaning by pneumatic machine 5 Cleaning by chisel 6 Surroundings Total dust < 50pm mg/m3 Respiratory dust < 5pm mg/m3 22.4 10.7 17.8 - 7.6 14.6 8.6 57.4 - 4.64 23.9 19.5 2.49 SiO2 % 7.9 8.3 12.7 16.1 29.6 18.3 18.7 Source: NILP, 30 October, 1998. As seen in Table 7, all dust samples exceeded the standards by a minimum of 1.3 times (in the area near the steel-melting furnace) and by a maximum of 14.3 times (where cleaning casts with a pneumatic machine). The percentage of free silica fluctuated between 8 and 30 per cent, especially in the mould-removal and cast-cleaning areas, which were considered the most dangerous because of their high dust concentrations and close exposure. Workforce According to statistical data for 1995-1998, foundry worker numbers tended to decrease, from 157 people in 1995 to 121 in 1998. (See Table 8.) Working year <5 6-10 11-15 16-20 21-25 26-30 > 30 Total Table 8: Number of foundry workes in 1995 - 1998 1995 1996 1997 male female total male female total male female total male 13 0 13 5 0 5 10 0 10 10 15 5 20 13 5 18 5 2 75 43 3 46 40 3 43 31 1 32 31 41 13 53 35 10 45 34 7 41 34 13 2 15 10 2 12 11 7 18 11 7 2 9 5 1 6 10 1 11 10 1 0 1 0 0 02 0 22 133 24 157 114 21 135 103 18 121 103 1998 female 0 2 1 7 7 1 0 18 total 10 7 a 41 18 11 2 121 17 The data in Table 9 shows changes in the number of foundry workers with the same work history (in percentages). Table 9: Percentage of foundry workers divided by the working year Working year 1995 (%) 1998 (%) < 5 8.3 8.3 6-10 5.8 12.7 11-15 26.4 29.3 16-20 33.9 33.8 21-25 14.9 9.6 26-30 9.0 5.7 > 30 1.7 0.6 The number of workers with a work history of fewer than 20 years tended to remain unchanged or increase slightly, but those with more than 20 years tended to decrease. The latter had retired or transferred to other work. The number of female workers had changed very little, with 15 per cent in 1995 as opposed to 14.8 per cent in 1998. (See Table 8.) This was probably because most of them were working in the mould-making area, where work intensity was less and dust concentrations were low, so they were able to work more years than their male counterparts. Health evaluation Table 10: State of health of foundry workers in 1995 - 1998 Health category 1995 N0 % 1996 N0 % 1997 N0 % Excellent 2 2.4 8 9 5 5.4 Good 4 4.8 36 36 19 20.4 Normal 72 88 38 43 57 61.3 Poor 4 4.8 4 5 12 12.9 Very poor ------ Number of examined workers 82 100 88 100 93 100 1998 N0 % 4 3.7 8 7.5 77 72 18 16.8 -107 100 According to statistical data regarding worker health for 1995-1998, the percentage of those in "excellent" health was low (2-9 per cent), while those in the "normal" category was highest. This was a disadvantage for workers who enjoyed normal health and worked in hazardous environments, since the possibility of contracting silicosis was higher than it was among the workers in "good" health. 18 Incidence of silicosis HAMECO conducts good health care and occupational disease examinations. Examination results for silicosis follow: Table 11. Suspected cases of silicosis (0/1 P degree), cumulative data Working year <5 6-10 11-15 16-20 21-25 26-30 > 30 Total 1995 1996 1997 1998 mal femal total mal femal total mal femal total male femal tota ee ee ee el 0 0 00 0 00 0 0 0 0 0 0 0 00 0 00 0 0 0 0 0 5 1 65 1 64 0 4 7 0 4 7 2 9 7 3 10 8 1 8 4 1 8 2 0 23 0 36 3 6 4 3 7 0 0 00 0 02 0 2 3 0 3 0 0 00 0 00 0 0 0 0 0 14 3 17 15 4 19 16 4 20 18 4 22 Source: HAMECO. Table 12. Compensated cases of silicosis (cumulative data) Working year <5 6-10 11-15 1995 1996 1997 1998 mal femal total mal femal total mal femal total male femal tota ee ee ee el 0 0 00 0 00 0 0 0 0 0 1 0 11 0 11 0 1 1 0 1 2 1 32 0 22 0 22 02 16-20 21-25 5 1 64 2 64 5 6 2 2 4 4 0 43 0 32 0 2 4 0 4 26-30 > 30 1 0 11 0 12 0 23 0 3 0 0 01 0 11 011 01 Total 13 2 15 12 02 14 12 2 14 13 2 15 Comments 19 1. The percentage of silicosis cases (cases/total worker number) was relatively high. Table 13: Percentages of silicosis cases and compensated cases in 1995 -1998 1995 1996 1997 1998 Total worker numbers 157 135 121 121 cases 32 33 34 37 % cases 20.3 17.8 20.7 22.3 Compensated cases 15 14 14 15 % compensated cases 9.6 10.4 11.6 12.4 2. Silicosis cases in the steel foundry were higher than they were in the cast-iron foundry Table 14: Silicosis cases in the steel and cast-iron foundries 1995 996 997 Workshop Worker Worker Worker Case % Case % Case numbers numbers numbers Steel foundry 74 21 28.3 56 16 28.6 56 17 Cast-iron foundry 62 11 17.7 50 8 16 50 8 % 30.3 16 Worker numbers 998 Case 56 18 50 9 % 32.1 18 3. The percentage of silicosis cases among crane drivers was very high. Table 15: Silicosis cases among crane drivers 1995 Cranes Number of workers 13 Case 7 % 53.8 Number of workers 6 Total workers 157 7 4.5 121 1998 Case 3 3 % 50 2.5 4. The percentage of silicosis cases among female workers was lower, but remained alarmingly high. 20 Table 16: Silicosis cases among women workers 1995 1998 Female workers Worker numbers 24 Case 5 % 20.8 Worker numbers 18 Case 6 Total workers 157 5 3.2 121 6 % 33.3 5 5. Some confirmed silicosis cases were transferred to other jobs, some to other enterprises or retired, and two cases died. The majority remained in the foundry. Table 17: Occupational situation of workers having confirmed silicosis Work place 1995 1996 1997 1998 Still working in foundry 32 33 34 36 Transferred to other job 35 9 - Transferred to other enterprises - 1 1 - On pension 121 - Died -1 1 - Dust control measures Wetting down This technique was applied to the mould-making and mould shakeout areas. Dust emission was much reduced. Isolation Some drum-type cleaning machines were placed in isolated rooms. Although noise and dust emission levels were high, the workers were not directly exposed. These kind of hazards pollute the surrounding environment only by infiltration (through doors and window, for example). Ventilation The present ventilation systems were in poor repair. In order to reduce workers' exposure to dust, one pedestal fan had been installed to blow the dust away while the worker was standing upwind. This method, although it reduces dust exposure where it is installed, pollutes other areas. 21 Personal protective equipment (PPE) Cotton respirators were the only PPE used. Many kinds of cotton respirators were available, but those with eight cotton layers were the most widely used in the foundry. According to questionnaire responses from 100 workers, all workers used respirators for dust prevention, while 50 per cent also humidified their respirators before use to increase their efficiency. Management measures providing facilities for washing face and hands and changing clothes scheduling steel melting on the night-shift, aiming to reduce fumes and dust for the majority of workers assessing income based on a marking system (See below, Article 4.) Article 4: Coefficients for production units Determination of points Evaluation criteria Volume of work done Progress of work Quality of work Occupational safety House-keeping Work discipline Collaboration Total: Points Up to 30 to 20 to 10 to 10 to 10 to 10 to 10 Up to 100 Classification and determination of factor Total points 100 95 85 70 50 30-49 < 30 Class A A1 B B1 C C1 D Factor 1.2 1.1 1.05 1 0.9 0.85 0.8 The manager regularly audits the workplace to check whether workers are respecting regulations, and awards marks for each component of the point system. So the workers' income depends on how well they respect regulations in the course of all work activities. This method contributes to raising worker awareness of OSH matters in general, and silicosis prevention in particular. 22 Promotion and training HAMECO organizes an annual training course for its own workers, aiming to raise awareness of OSH issues. However, there has never been a training course specializing in the topic of silica dust prevention. This has instead been incorporated into the course of OSH. Future methods of dust control In order to increase product quality and market competitiveness, HAMECO has borrowed 160 billion VND from the Government, including 60 billion VND for new foundry technology, including measures to ameliorate areas and processes wherein workers are most exposed to silica dust: Mould-making. Furan (an organic by-product of oil refining) will be substituted for water and glass liquid, and a mix of Furan and diluted acid will be used to make moulds that are easily broken and which therefore emit less dust. Steel and cast-iron melting furnaces. Steel and cast iron will be melted in highcapacity, induction-type furnaces that emit less dust and fumes. Mould removal and cast cleaning. These processes will automated and contained in rooms with fume- and dust-control systems. The project to improve the foundry technology began at the end of 1998 and is going to finish in 2000. 3.2 The Electrical Engineering Company The Electrical Engineering Company (Ministry of Industry) specializes in the production of three-phase and single-phase electric motors. Production capacity is 26,000 pieces a year. The company has two production units: the assembly line is situated in Cau Dien, 10 kilometres north of the centre, and the foundry is in Chem, 7 kilometres from the assembly unit. Technical processes at the Hanoi Mechanical Company and the Electrical Engineering Company are similar in many ways. We discuss only those features that are different, in the section below. Technology Only cast iron is produced with capacity of 1,200 tonnes a year. Cast iron is melted in cupolas. Other processes are similar to that of in HAMECO. 23 Dust pollution Table 18: Silica dust concentration in different work stations. N0 Sampling place Percentage particle of Percentage of free silica Total dust Compared to concentration standard diameter<5 pm (%) (mg/m3) (times) (%) 1 Manual mould 80 44 6.6 1.6 breaking 2 Small-piece cleaning 55 40 3.3 - 3 Castings cleaned by 90 32 6.5 1.6 hand grinder Source: 1998 survey, Occupational Health Centre, Ministry of Industry. According to these measurements, dust pollution levels in this foundry are not high. Workforce Table Working year <5 6-10 11-15 16-20 21-25 26-30 > 30 Total 9: Number of foundry workers in 1995 - 1998 1995 1996 1997 mal femal total mal femal total mal femal ee ee ee 10 1 11 4 0 4 10 1 3 3 6 2 2 42 1 14 12 26 9 2 11 7 6 16 2 18 18 10 28 17 10 3 1 4 2 4 65 2 2 1 30 1 11 2 0 0 0 0 0 00 0 48 20 68 35 19 54 42 22 total 11 3 13 27 7 3 0 64 male 10 2 6 18 5 0 0 41 1998 femal e 1 1 6 10 3 1 1 23 tota l 11 3 12 28 8 1 1 64 In the period 1995-1998, the number of workers remained relatively stable. Workers with 11 20 years of experience were in the majority with 64.7 per cent (1995), 72.2 per cent (1996), and 62.5 per cent (1997-1998). The percentage of female workers was relatively high: 29.4 per cent (1995), 35.18 per cent (1996), and 34.4 per cent (1997-1998). As in HAMECO, most female workers worked in the mould-making process, where working conditions were less harmful and the work was relatively light. 24 Health evaluation Table 20: State of health of found ry workers in 1995 - 1998 Health category 1995 1996 1997 N. % N. % N. % Excellent 24 35.3 9 16.7 2 3.1 Good 27 39.7 26 48.1 25 39.1 Normal Poor 16 23.5 18 33.3 35 54.7 1 1.5 1 1.9 2 3.1 Very poor ------ Number of examined 68 54 64 workers 1998 N. % 1 1.55 19 29.7 34 53.1 9 14.1 1 1.55 64 Comments Workers' health has worsened year by year. "excellent" health category: declined rapidly from 35 per cent (1995) to 1.5 per cent (1998) "normal": increased from 23 per cent (1995) to 53.8 per cent (1998) "poor" increased from 2 per cent (1995) to 14.6 per cent (1998) "very poor": 0.8 per cent in 1998; not applicable before 1997 Incidence of silicosis Table 21: Suspected silicosis cases (0/1P degree), cumulative data Working 1995 1996 1997 1998 year male female total male female total male female total male female <5 - - - - - - - - - - - 6-10 - - - - - - - - -- - 11-15 16-20 21-25 26-30 > 30 Total 3 0 2 2 0 2 2 0 21 0 2 1 43 0 31 0 15 0 - - - 0 1 1 2 1 33 0 1 0 1 1 0 1 - - -0 1 - - - - - - 1 1 21 1 6 1 76 1 76 2 8 10 2 total - 1 5 3 1 2 12 25 Table 22: Compensated silicosis cases (Cumulative data) Working 1995 1996 1997 year male female total male female total male female total <5 - - - - - - - - - 6-10 - - -- - -- - - 11-15 - - - - - - - - - 16-20 1 1 - 1 1 2 1 1 2 21-25 1 - - - - - - - - 26-30 - - - 1 0 1 1 0 1 > 30 - - -- - -- - - Total 2 1 32 1 32 1 3 Source: Electrical Engineering Company. male - 3 - 1 6 1998 female - 1 - 0 1 total - 4 - 1 7 Comments 1. The incidence of silicosis was on the rise from 1995 to 1998, with an especially sharp increase in 1998. (See Table 23.) Table 23: Percentage of silicosis cases in 1995 - ' 998 Year Total workers Silicosis cases % suffered Compensated cases % compensated cases 1995 68 10 14.7 3 4.4 1996 54 10 18.5 3 5.6 1997 64 11 17.2 3 4.7 1998 64 19 29.7 7 10.9 2. The percentage of silicosis cases among female workers is low (tab.24) Table 24 : Percentage of silicosis cases among women Year 1995 1996 1997 1998 Total workers 68 54 64 Silicosis cases 2 2 3 64 3 Percentage (%) 3 3.7 4.7 4.7 26 3. Work activities with the highest percentage of silicosis cases appear in Table 25 Table 25: Silicosis cases in some work activities Number of workers Silicosis cases Percentage (%) Cast iron 19 5 26.3 grinding Cupola 19 4 21 Moulding 19 3 15.8 Dust-control measures already implemented Besides the classic methods applied in other enterprises, some improvements are evident in the foundry cleaning process: Cleaning of castings is restricted to an isolated room, far from the main production building. Sand and water shot-blasting is used to clean castings. This equipment is compact, easy to use, efficient, and inexpensive (about 20 million VND per unit). 27 3.3 NILP recommendations Dust-control measures Nowadays, electric-arc furnaces are a popular means of melting steel in Vietnamese foundries. To control emission of fumes, it is necessary to deal with two issues: As much of the pollutant emissions as possible must be collected. The collected air must be cleaned before being discharged into the atmosphere. Collection of gases is difficult and complicated, and the most costly part of the system is the cleaning device. In order to trap fumes effectively, foundries have to install hoods both above the furnace and again in the upper zones under the roof. However, installing a hood directly above the furnace obstructs furnace operations. Thus, the hood is often installed only higher, under the roof. This option is not very effective. It requires much more exhaust air, for one thing, and wind blows the fumes away from the hood opening, further reducing its effectiveness. Among other things, appropriate cleaning devices also have to be highly efficient at collecting gases and resistant to high temperatures. To meet these requirements, imported technology often uses a baghouse as a gas filter. Such filters, with an air flow rate of 100,000 cubic metres per hour, were installed in Viet Thanh and VICASA steel mills at an investment of US$550,000 each. Not only are the capital investment costs beyond the means of many companies, operation costs (power consumption, maintenance, etc.) also present big problems. The NILP suggests using scrubbers for collecting dust instead of baghouses. These devices have been applied at the Duyen Hai Mechanical Company (Hai Phong City) and the Hai Phong steel mill. Their effectiveness of trapping fumes at the hood is about 70 per cent, and their dust-cleaning efficiency is about 85 per cent. In combination with its high rate of discharge, this kind of system can maintain concentrations of dust at ground level within permissible limits. Total costs for such a fume- and dust-control system run about 600 million VND. For other dust sources such as material belt conveyers, stone-crushing machines, and grinding machines, the NILP proposes the popular cyclone with spiral vane guide dustcontrol method. This device has been used with success in many factories throughout the country. It collects soil, stone, and cement dust with an efficiency of 80 per cent. Among its advantages are simplicity of manufacture, low costs of capital investment and maintenance, moderate dust-trapping efficiency, and stability of operation. With an estimated cost of 200 million VND for a complete dust exhaust system of 30,000 cubic metres per hour, this is an appropriate means of control for most dusty processes. 28 Enclosing hood for belt conveyor... For dust sources where it is impossible to install exhaust ventilation system, various kinds of water suppression systems may be applied. The NILP has produced a good axial ventilator which can operate as mist equipment. This fan performs two functions: while it suppresses dust it also cools. The NILP has also studied a method that uses spray nozzles with good effect. In conclusion, depending on specific conditions, various dust-control measures may be appropriate: dust collection and cleaning by scrubber; dust collection and cleaning by cyclone with spiral vane guide; or dust suppression by axial mist fans or spray nozzles. Personal protective equipment. Interviews and direct observation shows that most workers wear respirators comprising 6, 8, or 12 layers of cotton. However, not all respirators are designed for silicosis prevention. Most of these respirators are not checked for quality, especially regarding their capacity to protect the wearer from respiratory dust. Therefore, even crane operators, who usually wear respirators, have suffered a high incidence of silicosis (more than 50 per cent of examined crane operators). Respirator quality clearly represents a problem. Some workers usually take respirators off when engaged in removing moulds. In interviews, workers said that they felt it was too difficult to breathe when wearing the respirators, especially after working for some time. This is not surprising, since a layer of dust collects on the surface of the respirator during use. The high work intensity in this activity already tires the workers, and they need more air to breathe; therefore they tend to take respirators off. But this behaviour can be dangerous, since dust in this area is more harmful than in the other stages due to its relatively small particle size, high concentrations, and high toxicity. A special type of respirator is needed for workers exposed to silica dust. Currently, only one type of respirator is used for workers engaged in all jobs. The NILP has produced respirators that are appropriate for protection against silica dust. Their use should be promoted. Promotion and training 29 Interviews with workers as well as managers at two pilot foundries revealed that none of the companies had organized training courses on prevention of silicosis. Nevertheless, top management at these companies understood to some extent the danger of silicosis, and had implemented measures such as the following: annual health checks, including chest X-rays rehabilitation for workers with poor health OSH regulations rescheduling hazardous processes, which can sometimes be operated at night to limit the number of people exposed to risk improved technology where possible Such managers were in the minority, however. Junior officers such as safety officers and production managers and, even more, workers have a very limited understanding of silicosis. Very few of them understand the mechanism underlying silicosis - for example, they do not know that only particles of less than 5pm can go deep into the alveoli and cause the disease, while larger particles can be retained in upper respiratory path or captured by common respirators. Neither do they realize that those areas where dust concentrations are not very high, but where there is a small particle size or a high proportion of free silica, are more dangerous than areas where dust concentrations are high but there are larger particles and less free silica. Many do not understand that silicosis is incurable. Clearly, these people should be trained and provided with at least a minimum knowledge of silicosis and methods of prevention. The NILP has organized many training workshops on OSH which include discussion of silicosis. More of these workshops are needed, as are training programmes for trainers. 30 4. Conclusions Based on reported materials and pilot surveys of the Hanoi Mechanical Company and Electrical Engineering Company, the following conclusions and suggestions can be offered: 1. Vietnamese foundry technology is obsolescent, with many processes being performed by hand. Over the last few years, especially since 1996, many foundries have had to close for lack of orders. The survivors are operating at less than full capacity (maximum 50 per cent of designed capacity). Given production problems and limited investment capital, most foundries cannot upgrade to advanced technology. Whatever can be done to improve the working environment has already been done (for example using green sand, wetting down, etc.), but improvements are limited and inadequate. In addition, a lack of dust exhaust systems results in dust concentrations exceeding permissible limits in most foundry workstations. 2. In consequence, worker health has worsened. Few fall into the health categories of "excellent" or "good"; the majority are classified as "normal". Only 40 per cent of foundries have workers chest X-rayed and examined for silicosis. Foundry workers are concentrated in provinces such as Hanoi, Quang Ninh, Thai Nguyen, and Can Tho and in the ministerial sectors of Heavy Industry and Transport. The percentage of silicosis victims in Viet Nam is 9.5 per cent (among these, 2.5 per cent are compensated). Female workers often perform light jobs such as making moulds, and fewer than 2 per cent suffer from silicosis. There are no child workers in state-owned foundries. The figures indicate that the current incidence of silicosis is much lower than it was in 1985. Possible explanations include these: The 1985 data were collected from factories with high-capacity foundries and large number of workers, where all the sample population had been given medical exams and chest X-rays. The 1998 data are simply statistics reported by provinces and industries. In many cases, these sources had not organized medical examinations or chest X-rays for workers exposed to silica dust. Recent technology improvements in processes such as mould-making have much reduced dust concentrations. Work intensity has declined due to lack of orders, with many foundries working only two or three days a week. Therefore, exposure to dust has decreased. The pilot survey of two Hanoi foundries shows that the incidence of silicosis victims, which was 20 per cent in average 1995-1998, was twice as high as that found nationwide. Female victims among the foundry workers account for fewer than 5 per cent. The number of silicosis cases in the steel foundry was 1.5 times higher than that in the iron foundry. More than 50 per cent of crane operators were found to have silicosis. Therefore, 31 attention should be given to these work places when considering methods of silica dust control. For example, the crane cabin should be enclosed and provided with filtered or bottled air. 3. To improve the working environment and, ultimately, to satisfy national standards, the basic measure is change in technological processes. Only by applying advanced technology can foundries eliminate the causes of silicosis. While the Vietnamese economy is in recession, such changes should be taken step by step. Priority should be given to the following processes: mould-making; cleaning of castings; and melting. 4. If technological changes are not practicable, the following improvements can in the meantime reduce exposure to silica dust: Isolate or enclose dust sources such as sand mixers, vibrating grids, and drum cleaners. Wet down floors and mould surfaces before removing castings; axial mist fans and water spray nozzles are among the appropriate equipment; Local dust exhaust ventilation systems play an important role in dust control for dusty processes such as mould removal, sand mixing, and steel melting. The NILP has designed hundreds of dust-control systems for industrial enterprises throughout the country. For steel processing, in particular, fume exhaust systems have been installed and operated successfully in the Duyen Hai Mechanical Company and Hai Phong Steel Mill. Scrubbers have been used as dust- and smoke-cleaning devices. This model could be widely applied for steel-melting furnaces in foundries. Employ an OSH point system in calculating workers' income. Income will depend how well they respect working regulations, including OSH regulations. This method also improves worker awareness of OSH issues. Use high-quality respirators. The NILP is producing a respirator that is very effective for foundry workers. Humidifying cotton respirators, meanwhile, does help to reduce the amount of dust inhaled. Organize training courses on silicosis and countermeasures. Priority should be given to training trainers. 5. Recommendations regarding systematic foundry reports: Collection of foundry information using Form 3 should continue so that data can be updated. The Presidium of the VGCL invests trade unions in cities, provinces, and industries where there are foundries with the responsibility for collecting Form 3 data and sending to the NILP. This should be done annually, with reports being sent by the end of November. The NILP needs financial support from the VGCL, with a total of about 20 million VND for remuneration of those who fill in Form 3 and send to the NILP and for the assessment of data. 32  The collected data then will be disseminated to all members of the national taskforces on the elimination of silicosis. 33 References 1. Asian-Pacific Newsletter on Occupational Safety and Health. Vol. 4, No. 2 (September 1997). 2. Encyclopaedia of Occupational Health and Safety, 4th edition, 1998. 3. Pham Van Hai, Dust control in the construction industry. Subproject of the state-level project coded KT 02.05 (1991-1995). 4. Thai Quang Hoe et al. Study and application of engineering methods for prevention of silicosis in Vietnamese foundries, 1981 -1985. 5. Nguyen Thi Hong Tu. Current situation of silicosis and coal pneumoconiosis in Viet Nam. Report presented at a National Workshop on the prevention of silicosis, April 1998. 6. Data on workers' health and occupational disease at the Hanoi Mechanical Company and the Electrical Engineering Company. 7. Reports on foundries from 20 provinces and cities and 5 industries. 34 Annex 1 FORM I Primary survey form Com City Year of Capacity Number of workers Silicosis cases Number of Accidents No pany (Province) Establish (Tonnes/ Total Male Female Total Male Female compensated -ment year) workers Other information. 1. Comment on current state of technological processes in the foundry 2. Measures already implemented for reduction of silica dust exposure 3. Plans to improve technology and working conditions Information to be sent to this address: Mr. Pham Van Hai 1. Yet Kieu, Hanoi National Institute of Labour Protection. 35 Annex 2 FORM 2 Personal questionnaire To help researchers and policy-makers form a basis for proposing scientific and technical measures and policies on improvement of working conditions, would you please to answer the following questions by marking an "x" in the appropriate blank squares? Thank you. 1. Sex: Male Female 2. Date of birth:.................. 3. Education: ...110 Profession:................................... . . . / 12 4. Name ofjob:......................................Workplace:....................................... 5. Number of working years:.............................Number of years for presentjob: 6. Level of skill: 7. Does presentjob satisfy you? Yes No No idea 8. How are present working conditions in comparison to previous? Better The same Worse No idea 9. Which hazards are you exposed to? Heat Cold Wet Dust Noise Vibration Radiation Chemicals Toxic gases Shortage of light Nothing 10. Do the following dangers exist in your workplace? Moving or sharp parts that are not covered Potential for electric shock Falling or flying objects Heat source/potential burns Erosion substances Potential for collapse Slipping Risk of falls 11. Which tools do you work with? Manual Machine New imported Explosion potential Modern Simple Very old How many years have you worked with the machine? . . . , years In what condition are the instruments, tools or machines with which you work? Good, convenient^ Good, inconvenient Safe Normal Bad, inconvenient^ Unsafe 36 12. What do you think about your work load? Heavy Medium Light 13. In your opinion, are working conditions improving? Yes No Difficult to answer 14. How many training courses on labour protection have you attended?.............. courses 15. Do you have any understanding of silicosis? Yes 16. Is personal protective equipment provided? No Little Yes No Provided by money Not provided 17. Did you have any work-related accidents last year? Yes No If yes, which part of body was injured?................................................................................................. Number of days off:...................... Number of accidents............................. 18. How often do you have a medical examination? Periodically Not periodically 19. Do you have occupational examinations for silicosis? Never Yes No If yes, how severely have you suffered?: Not severe enough to be compensated Compensated 20. What have you done to reduce exposure to silica dust? Write down the measures implemented: 37 Annex 3 FORM 3 Vietnam General Confederation of Labour National Institute of Labour Protection Survey for evaluating dust-prevention practices in Vietnamese foundries This survey supports the National Action Programme on the Prevention of Silicosis. The purpose of the survey is to (1) review current dust management practices; (2) identify needed improvements - especially low-cost dust-prevention practices that employers could implement immediately; and (3) assist the Government of Viet Nam as well as the Viet Nam General Confederation of Labour in future dust-management planning, for example, establishing new policies, legislation, and projects to improve working conditions and prevent silicosis. Please answer the questions or mark (X) in an appropriate blank square. Thank you. Company: ..................................................................................................................................... Year of establishment:............................................................................................................. Province (City):.............................................................................................................................. Industry:.............................................................................................................................................. Address: ......................................................................... Tel.: .................................................................... 1. Foundry description Designed capacity:................................................... Actual capacity (at present):....................................... Main products:............................................................. 1.1. Draw a simple flowchart of your foundry: 38 1.2. List main equipment and machines used in all workstations. Equipment (machines) Quantity Capacity Type Year commenced operation 2. The state of technological processes. 39 (Please mark (x) or fill in appropriate spaces). 2.1. Steel-melting furnace. Number of furnaces:.............................................. Type of furnace: + Electrode + Induction ... ... Dust/fume exhaust system? If yes, how does it work? Yes ... No Good . No good 2.2. Iron-melting furnace. Number of furnaces: ............................. Type of furnace: + Cupola ... + Induction ... Dust/fume exhaust system? If yes, how does it work? Yes ... No Good . No good 2.3. Moulding. Type of moulding Yes No + Dry ... ... + Green ... ... + Self dry ... ... + Moulding on sand floor ... ... + Moulding in flask ... ... + Other (list type)........................................................ Type of dry Yes + Dry in reflection furnace powered by coal ... + Dry in reflection furnace powered by oil ... + Dry in reflection furnace powered by gas ... + Dry by blowing Co2 gas ... + Self dry by mixing special chemical in mould ... No 2.4. Shakeout of mould. Manual . Vibrating grid ... Others: ................................................ Dust exhaust system? If yes, how does it work? Yes .No Good ... No good 40 2.5. Cleaning of castings. Manual ... Pneumatic tool ... Steel shot ... Sand-blasting ... Water shot-blasting ... Sand and water shot-blasting ... Dust exhaust system? Yes . No If yes, how does it work? Good . No good 2.6. Is sand recycled? Yes ... No ... If yes, is there a dust exhaust system? Yes If yes, how does it work? Good No No good 41 3. Health Category Health category Excellent Good Normal Poor Very poor Total of health examined workers 199)5 Number % 1996 Number o%/ 1997 N umber o%/ 1998 Number % 42 43 Workforce Working history (workinq years) 0-5 6-10 11-15 16-20 21-25 26-30 >30 Total male 1995 female total male 1996 female total male 1997 female total male 1998 female total male 1999 female total X- rays Working history (working years) 0-5 6-10 11-15 16-20 21-25 26-30 >30 Total male 1995 female total male 1996 female total male 1997 female total male 1998 female total male 1999 female total 44 Suspected cases of silicosis Working history (workinq years) 0-5 6-10 11-15 16-20 21-25 26-30 >30 Total male 1995 female total male 1996 female total male 1997 female total male 1998 female total male 1999 female total Confirmed or compensated cases of silicosis Working history (working years) 0-5 6-10 11-15 16-20 21-25 26-30 >30 Total male 1995 female total male 1996 female total male 1997 female total male 1998 female total male 1999 female total 45 5. Methods of controlling exposure to silica dust 5.1. Which measures of dust control have been used for each dust source? Workstation Preparation of moulding sand Dust source Respirable or total dust concent'n (mq/m3) SiO2 concent'n (%) Compared with standard Current methods of dust control Mould making Melting Shakeout of mould Cleaning of casting Sand Recycling Vietnamese standard Maximum permissible concentration of silica dust in ambient air at workplace Silica content (%) 100 50 up to 100 20 up to 50 5 up to 20 1 up to 5 <1 Total dust concentration (mg/m3) Average over Short-time 8 hrs sampling 0.3 0.5 1.0 2.0 2.0 4.0 4.0 8.0 6.0 12.0 8.0 16.0 Respirable concentration (mg/m3) Average over Short-time 8 hrs sampling 0.1 0.3 0.5 1.0 1.0 2.0 2.0 4.0 3.0 6.0 4.0 8.0 46 5.2. Personal Protective Equipment ( PPE). What kind of PPE is used? + Respirator (cotton) 6 layers 8 layers 12 layers ... ... ... + Half-mask ... + Other:.................................................................. Who supplies PPE to your company? + State- owned company + Private + Both ... ... ... How often is the PPE changed? + Weekly ... + Monthly ... + 3 mouths ... + > 3 mouths ... 5.3.Hygiene practices. Are there places for workers to wash hands and face before eat during break times? Yes ... No ... Are there bathrooms for showering and change of clothes? Yes . No . 5.4. How often is the working environment monitored? Frequency of monitoring 1995 1996 1997 1998 5.5. Company's OSH policy and health-care programme. There has been any training course on silicosis? Yes . No . If yes, + When the last one took place? + Who provides the training service? + How long does the course last? + How many workers attend the course? 47 In what way do you warn workers about the dangers of silicosis? + By posters ... + By giving bad points in competition ... + By cutting incentives ... How do you check worker awareness of the danger of silicosis? + By seeing workers wearing respirators . + By receiving complaints about dust and . suggestions for the improvement of workplaces. + Others 5.6. Measures need to be implemented in the future. Does company have any plan to: + Change the technological processes in foundry? Yes ... No ... If yes, For which workstation? Time of commencement and completion. + Install exhaust system for dusty processes? Yes . No . If yes For which dust source? Time of commencement and completion. + Others: 48 5.7. Suggestions and summary for implementing immediate dust prevention measures........................................................................................................................................ 49