Occupational Exposure to Chemical Agents in the Portuguese Foundry Industry

Transcription

1 Occupational Exposure to Chemical Agents in the Portuguese Foundry Industry J C Costa* * Instituto de Soldadura e Qualidade, Pt. Abstract This paper reports on a project on occupational exposure to chemical agents developed in the Portuguese foundry industry on , involving a sample of 15 foundries. A total of 148 exposure profiles to crystalline silica, metallic dust and fumes, total dust and mineral oil mist were determined through monitoring within the 234 similar exposure groups identified. The profiles are described in terms of statistical distributions whenever possible. The strategy followed allows for an adequate risk assessment fully in accordance to applicable legal requirements and to the risk assessment process. Actual practice reviews together with risk assessments provide the chance for improvements on companies practice and for public administration management aspects of compliance checking. Occupational exposure, chemical agent, risk, risk assessment, foundry. 193/1

2 Introduction The Portuguese foundry industry comprised in companies and employed 4100 direct workers. These companies delivered a total production of tons of casts, representing almost 4% of UE total production, for a total turnover of 300 x This production showed a steady increase in the period [1]. The production of metal castings is a complex process that is long associated with worker injuries and illnesses related to exposure to chemical agents [2]. In Portugal a study was carried out on the ferrous sub-sector during , showing several exposures that would be considered as non acceptable [3]. In Portugal legal requirements on occupational exposure are based upon the framework directive on occupational safety and health [4] complemented for chemical agents by the related individual directive [5]. The transposition of these documents into national law [6], [7] did keep their technical approaches even if they coexist with former legislation whose technical approach is no longer adequate [8]. This was partially a motivation to develop the project Professional Exposure to Chemical Agents in the Portuguese Foundry Industry [9]. Methodology The project Professional Exposure to Chemical Agents in the Portuguese Foundry Industry was composed by four interrelated phases, as described: Phase 1 - Sector characterization, describes the Foundry economic and social aspects, presents the technologies involved and related substances used in order to identify the hazards and risks within this context; Phase 2 - Occupational safety and health situation, describes the actual practices on this issue for the selected sample of foundries, addresses similar studies identified as bibliographic references and the incidence of occupational diseases in Portugal; Phase 3 - Professional exposure profile, determines the exposure profiles for similar exposure groups identified in the sample companies; Phase 4 - Strategy to legal requirements conformity, describes the suggested actions to attain conformity to legal requirements in a way that can be either compatible to a global approach of risk management or evidenced to any interested party. Actual risk management should be considered as a set of four processes where risk assessment is the first building block [10]. Risk assessment in the project was based on the traditional monitoring of the agent concentration in worker breathing area [11], [12]. However a coherent and well defined exposure assessment strategy was adhered to in order to 193/2

3 obtain data expressing in fact the health risk associated to the agent exposure [13]. This strategy comprehends two very important and complementary phases: qualitative risk characterization and quantitative risk determination. Qualitative risk characterization encompasses a basic characterization, the identification of similar exposure groups (SEG) and priority setting, while the quantitative risk determination encompasses the actual monitoring and data treatment to get a reliable exposure measurement, then the comparison to the occupational exposure levels. This allows for a risk assessment that is in full compliance with the requirements laid down in the legislative references. Experimental The basis to experimental work started with information gathering for each foundry related to: Workplace - technology, processes, equipment and products used and work activities carried out; potentially exposed workers; agents identification and characterization, including definition of occupational exposure levels; exposure controls in place; exposure history, if any. The information gathering was based upon relevant documentation and validated through actual visits to the foundries to locally witness activities, practices in use. The analysis of the information gathered and observation of actual conditions in the foundries led to: SEG identification; priority setting as to the SEG exposure determination. Table 1 provides an example of the set of SEG identified (eleven for this case) in a ferrous sub-sector foundry. Table 2 provides an example of the chemical agents identified for a specific SEG of a ferrous sub-sector foundry with the information on what exposure profiles were determined. The experimental work itself consisted on monitoring through atmosphere sampling in the workers breathing area of a selected SEG and for a specific agent. The samples obtained were subjected to laboratory analysis as specified in order to allow for a further determination of timeweighted averages. The sampling strategy used a sample dimension of 6 to allow the definition of the statistical distribution (whenever possible). The sampling parameters and laboratory analysis carried out followed the specifications of the National Institute of Occupational Safety and Health analytical methods [14]. Occupational exposure limits play a very important role in risk assessment of exposure to chemical agents as they are the risk criteria to which the 193/3

4 profiles are essentially compared to. In this project the Threshold Limit Values from the American Conference of Governmental Industrial Hygienists, edition 2001 [15] were retained as they have been the reference most widely used in Portugal and is deemed to be a very consistent system on this subject. Results The methodology used allowed the identification of 234 SEG in the 15 foundries studied. From these a total of 148 exposure profiles (88 in the FSS, 60 in the NFSS) were determined. The exposure profiles were spread over a total of 47 profiles on metals, 20 on silica, 20 on dust, total and 1 mineral oil mist for ferrous foundries and 37 on metals, 7 on silica, 11 on dust, total and 5 on mineral oil mist for non-ferrous foundries. For each profile a descriptive statistics was performed followed by a Wilk- Shapiro fitting test to a lognormal distribution. In the case of adequate fit the distribution parameters were calculated (geometric mean and standard deviation) and a statistical inference carried out to obtain the values for analysis. This consisted on the upper limit of the estimated arithmetic mean as derived from the Land method. In the case of a non fit situation the profiles were considered represented through the range of time weighted averages and their maximum value. Table 3 gives examples of these two situations for silica exposure in two different foundries. Foundry 1 has two SEG exposed (Abatement and Grinding) fitting to lognormal distribution which upper control limit show that exposures are not controlled (0,10 and 0,17). Foundry 2 has one SEG exposed that does not fit a lognormal so the description of the profile is no longer obtained trough the lognormal parameters. In this case the profile is not controlled as well. Discussion The project made clear that risk assessment of occupational exposure to chemical agents calls for a large set of activities involving different sectors of the companies and the consideration of very different but concurring aspects. The strategy used, by considering hazard identification, establishing risk estimation, evaluation thus allows for a further risk assessment based upon a very important set of data, including numerical data, statistically meaningful. In consequence it represents an important tool to exercise an effective risk management by supporting the activities related to the specific legal requirements. In the ferrous sub-sector 49 (56%) of the profiles determined represent controlled exposures. Uncontrolled exposures occur either to metals or to silica. The finishing operations allow for important levels of exposure. In the non-ferrous sub-sector 46 (77%) of the profiles determined represent controlled exposures. The actual practices deserve a technical analysis in a way to allow for improvements in the overall approach to risk assessment of occupational exposure. This improvement should concentrate on the basic methodology to follow and the corresponding evidences that should be produced. 193/4

5 Conclusions The Portuguese Foundry industry developed a project aimed at achieving a global knowledge of its situation in the field of occupational exposure to chemical agents. The results obtained suggest that this subject is a part of the overall risk management activities but the actual practices have an important space for improvements. These improvements should be centered on the adoption of a strategy that is in conformity with actual legal, technical requirements and can be made evident to interested parties such as the public administration. The quantitative analysis allowing for a robust and a dynamic risk assessment is of utmost importance. The industry is willing to disseminate the knowledge acquired with this project and widen its use namely to other agents such as the organic type ones. References 1. European Foundry Association CAEF. Data on Foundry Industry National Institute for Occupational Safety and Health (NIOSH): Recommendations for Control of Occupational Safety and Health Hazards Foundries. DHHS (NIOSH) publ. no U. S. Department of Health and Human Services. Centers for Disease Control, Ataíde, António, Silva, Eduardo D., Ribeiro, Fernando P., Rodrigues, Manuel V., Macedo, Ricardo, Riscos de Doenças Profissionais nas Fundições Portuguesas de Ferro e Aço (Avaliação e Prevenção): 2.ª Ed. Caixa Nacional de Seguros de Doenças Profissionais, Lisboa, Council Directive 89/391/EEC of 12 June 1989 on the introduction of measures to encourage improvements in the safety and health of workers at work, OJ EC L Council Directive 98/24/EC of 7 April 1998 on the protection of the health and safety of workers from the risks related to chemical agents at work (fourteenth individual Directive within the meaning of Article 16(1) of Directive 89/391/EEC) OJ EC L Decree Law nº 441/1991 of 14 November - Transposition to internal legal framework of Council Directive 89/391/EEC. 7. Decree Law nº 290/2001 of 16 November -Transposition to internal legal framework of Council Directive 98/24/EC, and Commission Directives 91/322/EEC and 2000/39/EC. 8. Regulamento de Segurança e Higiene no Trabalho dos Estabelecimentos Industriais (Portarias nº 53/71 and 702/80) INCM Costa J C, Dias A M, Peixoto A R, Chaves M B, Ribeiro, C S, Malheiros, L F, Costa, H M: Exposição Profissional a Agentes Químicos na Indústria da Fundição Portuguesa. ISHST /5

6 10. International Organization for Standardization (ISO): Risk management Vocabulary. Guidelines for use in standards. ISO DGUIDE 73, European Committee for Standardization (CEN): EN 1540:1998. Workplace atmospheres Terminology European Committee for Standardization (CEN): EN 689:1995. Workplace atmospheres Guidance for the assessment of exposure by inhalation to chemical agents for comparison with limit values and measurement strategy, Mulhausen, J R and Damiano, J: A Strategy for Assessing and Managing Occupational Exposures, Second Ed., U. S. Department of Health and Human Services: NIOSH Manual of Analytical Methods 4th Ed. DHHS (NIOSH) Publ. Nº American Conference of Governmental Industrial Hygienists (ACGIH): 2001 TLVs and BEIs, Threshold Limit Values for Chemical Substances and Physical Agents, Biological Exposure Indices Acknowledgements The author wants to thank all support provided for the project and this paper by Manuel Botelho Chaves and Carlos Silva Ribeiro (Associação Portuguesa da Fundição) e Ana Maria Dias (Instituto de Soldadura e Qualidade). A specific thanks goes to Instituto para a Segurança e Higiene do Trabalho whose financial support made the project possible altogether. Tables Table 1 Identified similar exposure groups ferrous foundry Similar exposure Composition (Operators) group (SEG) 1 Fusion 2 Pouring 3 Furnace and accessories maintenance 4 Green sand preparation 5 Green sand casts abatement 6 Other sand types preparation 7 Other sand types casts abatement 8 Core making 9 Grinding 10 Welding and cutting 11 Wood preparation 193/6

7 Table 2 SEG chemical agents exposure Operation / workplace Fusion Chemical agent SEG Notes Dust, total Dust, respirable Iron oxide (fumes) Manganese Mg oxide (fumes) Cr (III) Cr (VI) Ni, metal Ni, insoluble compounds Mo Carbon dioxide Carbon monoxide Silica Ba Al (dust and fumes) 1 Professional Exposure to: Iron oxide (fumes) Manganese Cr (VI) Dust, total Table3 Silica exposure - profile characteristics TWA Distribution TWA Foundry SEG (mg.m -3 DF max Profile ) GSD UCL (mg.m -3 ) control 5/ Abat. 0,01-0,090 Y 2,2 0,10 - N F1 9/ Grind. 0,035-0,11 Y 1,6 0,17 - N F2 2/ Fusion 0,01-0,034 N - - 0,034 N 193/7