With the development of nanotechnology, nanomaterials are used in various fields. Therefore, the interest regarding the safety of nanomaterial use is increasing and much effort is diverted toward establishment of exposure assessment and management methods. Occupational exposure limits (OELs) are effectively used to protect the health of workers in various industrial workplaces. This study aimed to propose an OEL for domestic multi-walled carbon nanotubes (MWCNTs) based on animal inhalation toxicity test. Basic procedure for development of OELs was examined. For OEL estimation, epidemiological study and quantitative risk assessment are generally performed based on toxicity data. In addition, inhalation toxicity data-based no observed adverse effect level (NOAEL) and benchmark dose (BMD) are estimated to obtain the OEL. Three different estimation processes (NEDO in Japan, NIOSH in USA, and Baytubes in Germany) of OELs for carbon nanotubes (CNTs) were intensively reviewed. From the rat inhalation toxicity test for MWCNTs manufactured in Korea, a NOAEL of 0.98 mg/㎥ was derived. Using the simple equation for estimation of OEL suggested by NEDO, the OEL of 142 μg/㎥ was estimated for the MWCNT manufacturing workplace. Here, we used test rat and Korean human data and adopted 36 as an uncertainty factor. The OEL for MWCNT estimated in this work is higher than those (2-80 μg/㎥) suggested by previous investigators. It may be greatly caused by different physicochemical properties of MWCNT and their dispersion method and test rat data. For setting of regulatory OELs in CNT workplaces, further epidemiological studies in addition to animal studies are needed. More advanced technical methods such as CNT dispersion in air and liquid should be also developed.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 일반적인 직업노출기준 산정방법
  2.2. 직업노출기준 연구사례
  2.3. 국내 다중벽 탄소나노튜브 제조 작업장에 대한직업노출기준 산정방법
 3. 결과 및 고찰
  3.1. NOAELR 산정
  3.2. 직업노출기준 산정
 4. 결 론
 감사의 글

• 김종범(고려대학교 그린스쿨(에너지환경정책기술대학원), 한국과학기술연구원 환경복지연구단, Green School (Graduate School of Energy and Environment), Korea University, Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST)) | Jong Bum Kim
• 김경환(동일시마즈(주) 기술연구소, Technical Research Center, Doing-il Shimadzu Corp.) | Kyung Hwan Kim
• 최병길(한국건설생활환경시험연구원 바이오융합연구소, Bioconvergence Technology Laboratory, Korea Conformity Laboratories (KCL)) | Byung-Gil Choi
• 송경석(한국건설생활환경시험연구원 바이오융합연구소, Bioconvergence Technology Laboratory, Korea Conformity Laboratories (KCL)) | Kyung Seuk Song
• 배귀남(고려대학교 그린스쿨(에너지환경정책기술대학원), 한국과학기술연구원 환경복지연구단, Green School (Graduate School of Energy and Environment), Korea University, Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology (KIST)) | Gwi-Nam Bae Corresponding author