Occupational exposure limits in Europe and Asia – Continued divergence or global harmonization?

Abstract

Occupational exposure limits (OELs) are used as a risk management tool aiming at protecting against negative health effects of occupational exposure to harmful substances. The systems of OEL development have not been standardized and divergent outcomes have been reported. However some harmonization processes have been initiated, primarily in Europe. This study investigates the state of harmonization in a global context. The OEL systems of eight Asian and seventeen European organizations are analyzed with respect to similarities and differences in: (1) the system for determining OELs, (2) the selection of substances, and (3) the levels of the OELs. The majority of the investigated organizations declare themselves to have been influenced by the American Conference of Governmental Industrial Hygienists (ACGIH), and in many cases this can be empirically confirmed. The EU harmonization process is reflected in trends towards convergence within the EU. However, comparisons of Asian and European organizations provide no obvious evidence that OELs are becoming globally harmonized.

Introduction

Environmental and occupational exposure to chemicals can potentially cause negative health effects. Regulatory action aiming at protection against such effects is developed and implemented at the national and international level. For the work environment, occupational exposure limits (OELs) are widely used as a risk management tool. These standards restrict the allowable concentrations of harmful substances in the air. The rationale behind OELs is that if the exposure is sufficiently low, then no or acceptably small negative health effects will arise. The final values of OELs however often depend not only on health risk assessments based on scientific evidence, but also on socioeconomic and technological factors. Consequently, they are influenced by philosophical objectives and the economic situation, and the outcome of the OEL setting process may differ considerably from country to country (Hansson, 1998a, Schenk et al., 2008a, Schenk, 2010). National agencies responsible for occupational health and safety produce lists of OELs reflecting their national policies. Proposals for more standardized approaches leading to more harmonized outcomes have been voiced (Liang et al., 2006, Wong, 2003).

The American Conference of Governmental Industrial Hygienists (ACGIH) developed a system for setting limit values, and its first list of OELs, called Threshold Limit Values (TLVs), was published in 1946. In spite of widespread criticism for insufficient scientific basis (Castleman and Ziem, 1988, Roach and Rappaport, 1990, Rappaport, 1993, Hansson, 1998a, Hansson, 1998b, Rudén, 2003), some national agencies still use the TLVs as a benchmark for setting OELs (Piney, 1998, Schenk et al., 2008a).

In recent years, issues of risk management of occupational industrial hazards have become increasingly globalized. Asian countries have become the main manufacturers of goods for other nations all over the world, which brings them to the spotlight of this interest. As an example, China is considered to be the largest producer of coal, steel and cement and is also the world’s largest exporter of electronics products (OECD, 2005). China’s global share of manufacturing reached nearly 14% in 2007, and together with Japan and South Korea the three countries reached almost 30%. Approximately 200 million workers in China are potentially exposed to industrial chemicals (Liang et al., 2006). Similar tendencies apply, although to lesser extent, to other Asian countries. Increasing rates of work-related diseases among Asian populations have been repeatedly reported (Takahashi and Karjalainen, 2006; Todd et al., 2008, Kim et al., 2010).

The regulatory actions by different authorities aiming at controlling chemical hazards at workplaces in different countries and regions in Asia have been described previously in several publications (Wong, 2006)¹. Most of these regulatory systems have been developed on the basis of the ACGIH-TLVs. As an example, it has been reported that 20% of the OELs in China have been adopted from existing standards set in other countries, predominantly the ACGIH-TLVs (Liang et al., 2006). Similarly, the OELs implemented in Hongkong are based on the TLVs of ACGIH and the former OELs of the UK. Many of the OELs in Taiwan were adopted from the most recent ACGIH-TLVs or the Permissible Exposure Limits (PELs) of the US Occupational Safety and Health Administration (OSHA) (Shih et al., 2006). The first set of OELs in South Korea was announced by the Minister of Labour in 1986. At that time, it was identical to the ACGIH TLVs. However until 2008, the Minister of Labour of South Korea has notified revised OELs for 126 chemicals, and 58 of them were lowered to half or less than half of the original OELs (Jeong et al., 2010). Almost all health and safety monitoring service agents in South Korea have compared their monitoring results with both the South Korean OELs and the updated ACGIH TLVs. For Singapore, the OELs of USA, EU, Australia, Canada, and Japan are all reported to have influence (Tang et al., 2006). The 1999 TVLs of ACGIH were adopted as OELs for the majority of the regulated substances in Malaysia (Rampal and Nizam, 2006). According to Takahashi and Higashi (2006), the committee members of the Japanese OEL committee consider the TLVs of ACGIH to be one of the most reliable sources of information for the preparation of OELs (Takahashi and Higashi, 2006). The Japanese OELs have influence in China and Singapore (Liang et al., 2006, Tang et al., 2006).