This study was conducted at an automobile assembly line located in Kyonggi-do, Korea from January 16 to February 28, 1995. The purposes of this study were to assess worker exposures to hand-arm vibration and the performance of gloves for reduction of vibration. The exposure to vibration was measured using to the ISO 5349(1986) method. Vibration acceleration and frequency spectra for each tool were determined on-line replicating actual working conditions and analyzed together with exposure time for evaluating individual worker exposure. Eight pneumatic hand tools, 60 workers exposured to hand-arm vibration, and three pairs of gloves were involved in this study. Results are summarized as follows. 1. Dominant frequencies of vibration for all tools(n=8) measured in this study ranged from 250 Hz to 800 Hz. 2. There was no significant correleration between dominant frequencies and free running speed (p>0.05). 3. Total predicted exposure times of using impact, hammer type did not exceed 40 minutes, but metal finish task, using grinder and sander exceeded 40 minutes. Total exposure time affected significantly the frequency-weighted, 4 hr equivalent acceleration. 4. Predicted prevalence and observed exposure period data were compared in workers(n=60), according to ISO 5349. In this results, 23(50.0 %) and 24(48.07 %) persons exceeded the mean latency periods for vibration-induced white finger(VWF) at 10 % (n=46) and 50 % (n=52) standards, respectively. On the basis of ISO equation, mean latent periods for VWF were 3.23, 4.72 years at 10 %, 50 % standards, respectively. 5. Reduction of vibration by gloves was evaluated. Since impact pneumatic tools produced low frequency vibrations, conventional gloves did not provide any protection. Gloves A and C amplify somewhat the signal at frequency below 400 Hz; the attenuation increases progressively by frequency to reach 18 dB ($7.94{\times}10^{-6}m/s^2$) at 1,000 Hz, slightly worsening Glove B did not provide any protection and made the situation slightly worse. However, since they make the hands warm, the occurrence of vibration-induced white fingers may be reduced.

This study was designed to survey exposure levels of formaldehyde among workplaces in some plywood industries and to compare three sampling methods including the impinger method(IM, NIOSH method No. 3500), the solid sorbent tube method(SS, NIOSH method No. 2541), and the passive bubbler monitor method(PB, SKC). The survey was conducted in seven particle board manufacturing factories, two resin manufacturing factories and two plywood manufacturing factories in Incheon area during the period from March 6 to April 20, 1995. The workplaces included were the hot/cold press, the roller/spreader, the soaking/drying, and the reaction/mixing areas. The results were as follows; 1. The average(GM, GSD) concentrations of formaldehyde by sampling methods were 0.11(4.43) ppm by IM, 0.27(2.03) ppm by SS, and 0.29(2.04) ppm by PB, respectively. The concentrations by 1M method were statistically very significantly lower than those of SS and PB methods, particularly at low air borne concentrations of formaldehyde (p<0.001). 2. The area average concentrations of formaldehyde by workplaces measured with PB bubblers were 0.23(2.08) ppm from the press, 0.23(1.77) ppm from the spreader, 0.24(1.51) ppm from the soaking, and 0.46(1.96) ppm from the reaction areas, respectively. The personal average concentrations of formaldehyde by workplaces measured with PB bubblers were 0.30(1.77) ppm from the press, 0.33(1.54) ppm from the spreader, 0.36(1.46) ppm from the soaking, and 0.84(1.19) ppm from the reaction areas, respectively. 3. No statistically significant differences of formaldehyde concentrations among workplaces except the reaction area(p<0.001) were found. 4. Formaldehyde concentrations from personal samples were higher than those of from area sam pies in all workplaces studied. But no statistically significant differences of formaldehyde concentrations both area and personal samples were found. In conclusion, this study found that although formaldehyde concentrations in some plywood industries in Incheon area were below the regulatory limit of 1 ppm, they were over the limits recommended by NIOSH and ACGIH. This study also suggests that the impinger method may underestimate true formaldehyde concentrations. It implies that there will be more workplaces not meeting current regulatory limit if either the solid sorbent or passive bubbler methods were used instead of the impinger method. It is suggested that passive monitors will be a reasonable alternative for area and personal sampling of formaldehyde if the accuracy and validity of passive monitors be verified before use.

Benzidine, an aromatic amine used primarily in the manufacture of azo dyes, is recognized as a urinary bladder carcinogen in humans. In rats, mice, and hamsters, chronic exposure to benzidine resulted in tumors of the liver. The present study was undertaken to suggest analyzing the metabolites of benzidine with the optimal condition, identify the metabolites of benzidine, and observe time variance of the metabolites in the isolated perfusated rat liver. N-acetylbenzidine was synthesized by acetylation of benzidine with acetic anhydride and separated by thin layer chromatography(TLC) and high performance liquid chromatography(HPLC). To analysis benzidine and the metabolites of benzidine, HPLC operating condition has been optimized by means of preliminary experiment. The mobile phase consisted of acetonitrile(37%) in phosphate buffer, flow rate maintained at 1.0 ml/min. Optimal detective conditions were electrochemicaldetector(ECD) at 0.75 V for benzidine and N-acetylbenzidine and ultravioletdetector(UVD) at 287 nm for N,N'-diacetylbenzidine. The separation system was composed of a guard column and a separation column(Polymer C18, $4.6{\times}250cm$) at a temparature of $40^{\circ}C$. The perfusion system was equilibrated for 30 minutes before addition of benzidine to the perfusate. Samples of the perfusate were collected at time intervals(0, 10, 20, 30, 60, 90, 120 min) during the 2 hour perfusion. Before analyzing samples by HPLC/ECD/UVD, samples had been treated with sep-pak. Samples of perfusate analyzed by HPLC/ECD/UVD and the metabolites of benzidine in the isolated perfused rat liver were N-acetylbenzidine and N,N'-diacetylbenzidine. Benzidine metabolized over 60% during the initial 30 minutes of perfusion, extensively by 1 hour, and was undetectable in the perfusate. N-acetylbenzidine increased by 30 minutes of perfusion, declined. N,N'-diacetylbenzidine increased the 0-90 minutes period, remained constant during the 90-120 minutes period.

Respirator fit testing is required before entering specific work environmentals to ensure that the respirator worn satisfies a minimum of fit and that the user knows when the respirator fits properly. The fit of a respirator can be determined by qualitative (QLFT) or quantitative fit test (QNFT). The QNFT, having been universally accepted more than the QLFT, provide an objective and numerical basis by measuring a fit factor (FF). Until a few years age, only one QNFT technigue was available and accepted by U.S. Occupational Safety and Health Administration (OSHA) regulations. In the 1980's and 1990's, several new and fundamentally different QNFT methods were developed. Two of the newer methods are commercially availale and are accepted by OSHA as suitable alternatives. In this articles, the principle of operation of each ONFT technique is explained and each technique's major advantages and disadvantages are pointed out. Emphasis is given to negative-pressure air-purifying respirators, as they are in most frequent use today. The requirements and recommendations for fit testing positive-pressure respirators are discussed as well. Finally, the presently available QNFT standards and regulations are summarized to assist the user in making fit testing decisions.

This study was conducted to evaluate breakthrough characteristics of respirator cartridge using multi-organic vapors, including carbon tetrachloride, trichloroethylene, and toluene. The organic vapors were used as single phase, binary system, and ternary system. The results are summarized as follows. 1. Organic vapors studied were 1,000 ppm, 750 ppm, 500 ppm and 250 ppm in single phase. Carbon tetrachloride having the highest molecular weight showed the breakthrough first, and breakthrough sequency by organic vapor was dependent on its molecular weight. The 10% breakthrough times at 1,000 ppm of organic vapor were 97 minutes for carbon tetrachloride, 129 minutes for trichloroethylene and 135 minutes for toluene. 2. When concentrations of organic vapors were at levels of the Threshold Limit Values, the lives of the respirator cartridges were 122 hours in carbon tetrachloride, 18 hours in trichloroethylene and 28 hours in toluene. 3. In the binary system at a total concentration of 1,000 ppm with carbon tetrachloride and trichloroethylene, breakthrough times ranged from 104 minutes to 125 minutes, which were longer than 97 minutes in a single phase (1,000 ppm) for carbon tetrachloride, but shorter than breakthrough times for TCE and Toluene. 4. Breakthrough times in the binary system with carbon tetrachloride and toluene were 131~132 minutes. 5. Breakthrough times in the ternary system with carbon tetrachloride, toluene, and trichloroethyl ene were $120{\pm}8$ minutes, which were longer than 97 minutes in the single phase (1,000 ppm) for carbon tetrachloride, equal to 129 minutes for trichloroethylene, and shorter than 135 minutes for toluene. Those were almost similar to $124{\pm}9$ minutes of breakthrough times in the binary systems.

This study was performed to estimate total dust concentrations and particle size distribution of wood dust in the furniture and sawmill industries. To compare total wood dust concentrations, two samplers recommended by the American Conference of Governmental Industrial Hygienists and by the National Institute for Occupational Safety and Health were used. Concentration data were analyzed by paired-t tests using the SAS program and two parameters of the particle size distributions were determined by histogram. The results were as follows: 1. Particle size distributions showed a unimodal pattern in cutting and a bimodal in sanding operations. Mass median aerodynamic diameters(MMAD) were $17.35{\mu}m$ in cutting, and $1.39{\mu}m$ for small mode and $18.89{\mu}m$ for large mode in sanding operations. The proportions of particle size larger than $9.8{\mu}m$ estimated by the impactor were 61.16 % in cutting and 62.33 % in sanding operations, respectively. 2. The average personal total dust concentrations measured by IPM sampler were $17.12mg/m^3$ (GSD=1.45) from indoor samples, $2.97mg/m^3$(GSD=1.90) from outdoor samples in cutting, and $8.01mg/m^3$(GSD=1.58) from sanding operation. And those of by 37 mm closed-face cassette were $9.12mg/m^3$(GSD=1.46), $1.06mg/m^3$(GSD=1.99) from cutting, and $3.32mg/m^3$(GSD=2.16) from sanding operations. 3. The average area total dust concentrations measured by IPM sampler were $1.88mg/m^3$(GSD=2.04) from indoor cutting, $4.76mg/m^3$(GSD=2.83) from indoor sanding operations. And those of by 37mm closed-face cassette were $0.49mg/m^3$(GSD=2.34) from cutting, and $1.32mg/m^3$(GSD=3.03) from sanding operations. 4. The ratio of personal total dust concentrations measured by 37 mm closed-face cassette to those by IPM sampler were 35.7 %, 53.3 % from cutting, and 41.4 % from sanding operations. 5. The ratio of area total dust concentrations measured by 37 mm closed-face cassette to those by IPM sampler were 26.1 % from cutting, and 27.7 % from sanding operations. 6. A statistically significant difference of total dust concentrations between the 37 mm closed-face cassette and the IPM sampler was found.

다량의 연을 사용하는 제조업 중에서 7개의 축전지 제조업, 3개의 폐전지 제련공장, 그리고 2개의 연분 및 광명단을 제조 또는 사용하는 사업장 총 11개 대상 사업장에서 정기 보건관리시 혈중 Zinc Protoporphyrin 농도를 고려하여 생산직 남자 근로자 234명을 선정, 혈액에서 혈중연, 혈중 ZPP, 혈색소 등을 측정하고 소변에서 ${\delta}$-ALA 배설량을 비색법과 HPLC법으로 분석하여 그 차이점을 확인하고 연노출 지표들과의 관련성을 조사하여 연중독 판정기준의 새로운 기준을 마련하기 위하여 본 연구를 시도한 바 결과는 다음과 같다. 1. 비색법과 HPLC법에 의한 요중 ${\delta}$-ALA 배설량은 높은 상관성이 있으나 비색법이 HPLC법 보다 2 mg/L 정도 높게 측정되었다(r = 0.989, 회귀식 ; HALA = - 0.8194 + 0.8110 ${\times}$ CALA) 2. 요중 ${\delta}$-ALA 배설량은 두 방법 모두 혈중연 및 혈중 ZPP 농도와의 상관계수가 각각 0.46, 0.37 이상이었으며, ${\delta}$-ALA 배설량을 대수변환하였을 때는 상관계수가 0.63, 0.57로 높아졌으며 통계적으로도 유의하였다. 3. 혈중 ZPP를 독립변수로, 비색법과 HPLC법에 의한 요중 ${\delta}$-ALA 배설량을 종속변수로 한 단순회귀방정식은 다음과 같다. CALA = 2.0421 + 0.0341 ${\times}$ ZPP $R^2=0.1385$ p = 0.0001 HALA = 0.8006 + 0.0280 ZPP $R^2=0.1389$ p = 0.001 4. 혈중연을 독립변수로, 비색법과 HPLC법에 의한 요중 ${\delta}$-ALA 배설량을 종속변수로 한 단순 회귀 방정식은 다음과 같다. CALA = - 0.4134 + 0.1545 ${\times}$ PbB $R^2=0.2085$ p = 0.0001 HALA = - 1.2893 + 0.1287 ${\times}$ PbB $R^2=0.2154$ p = 0.0001 5. 비색법과 HPLC법에 의한 요중 ${\delta}$-ALA 배설량을 대수변환하였을 때 혈중연 및 혈중 ZPP를 독립변수로 하는 회귀식은 다음과 같다. logHALA = 0.3078 + 0.0060 ${\times}$ ZPP $R^2=0.3329$ p = 0.0001 logCALA = 1.0189 + 0.0044 ${\times}$ ZPP $R^2=0.3290$ p = 0.0001 logHALA = - 0.0221 + 0.0246 ${\times}$ PbB $R^2=0.4046$ p = 0.0001 logCALA = 0.7662 + 0.0184 ${\times}$ PbB $R^2=0.4108$ p = 0.0001 6. 요중 ${\delta}$-ALA 배설량에 대한 연중독 주의한계의 cut-off point를 5 mg/L로 하였을 경우 혈중연과 혈중 ZPP의 주의한계에 대한 비색법의 누적 빈도가 HPLC법 보다 높았으며, 따라서 HPLC법의 cut-off point를 3 mg/L로 하였을 때 비색법과 좋은 일치도를 보였고 연노출지표들과 량-반응 관계를 나타내었다. 이상의 결과로 연중독 판정기준의 주의한계와 선별한계의 개정이 필요하나 남자 근로자들만의 연구이므로 여자 근로자에 관한 연구가 추가로 필요하다고 생각된다.

This study was conducted to establish model between lead and ZPP concentration in blood of workers exposed to lead. Workers employed in secondary smelting manufacturing industry showed $85.1{\mu}g/dl$ of blood lead level, exceeding $60{\mu}g/dl$, the Criteria for Removal defined by Occupational Safety and Health Act of Korea. Average blood lead level of workers in the battery manufacturing industry was $51.3{\mu}g/dl$, locating between $40{\mu}g/dl$ and $60{\mu}g/dl$, the Criteria for Requiring Medical Removal. Blood lead level of in the litharge and radiator manufacturing industry was below $40{\mu}g/dl$, the Criteria Requiring Temporary Medical Removal. Blood lead levels of workers by industry were Significantly different(p<0.05). 50(21 %) showed blood lead levels above $60{\mu}g/dl$, the Criteria for Removal and 66(27.7 %) showed blood lead levels between the Criteria for Requiring Medical Removal, $40-60{\mu}g/dl$. Thus, approximately 50 percent of workers indicated blood lead levels above $40{\mu}g/dl$, the Criteria Requiring Temporary Medical Removal and should receive medical examination and consultation including biological monitoring. Average ZPP level of workers employed in the secondary smelting industry was $186.2{\mu}g/dl$, exceeding above $150{\mu}g/dl$, the Criteria for Removal. Seventy seven of all workers(32.3 %) showed ZPP level above $100-150{\mu}g/dl$, the Criteria for Requiring Medical Removal. The most appropriate model for predicting ZPP in blood was log-linear regression model. Log linear regression models between lead and ZPP concentrations in blood was Log ZPP(${\mu}g/dl$) = -0.2340 + 1.2270 Log Pb-B(${\mu}g/dl$)(standard error of estimate: 0,089, ${\gamma}^2=0.4456$, n=238, P=0.0001), Blood-in-lead explained 44.56 % of the variance in log(ZPP in blood).

A new type of passive samplers were designed and produced by authors. After evaluating the quality of activated carbon by measuring recovery rate of organic vapors and steadiness of sampling rate, activated carbon with 30 - 35 mesh produced by Company S in Korea was selected. In each passive sampler, an amount of 400 mg of the activated carbon was filled in 25-mm cassette and covered by fixed screen (or wire screen with 100 mesh). In addition to the fixed screen, a wind screen (or wire screen with 300 mesh) was also attached at outer face. The sampling rate of the new Korean passive samplers was estimated Conclusions obtained in the study are as follows. 1. Sampling rates of the newly developed Korean passive samplers were affected by sampling time. For n-hexane, sampling rates of 15- and 60-minute samples were 70.92 and 37.45 ml/min, respectively. Sampling rate of both 200- and 450-minute samples was 25.96 ml/min. It is concluded that, when passive samplers are used for measuring organic vapors, samples be collected longer than 60 minutes. 2. Sampling rate of the passive samplers was also affected by airborne concentration of organic vapors. Lower sampling rates were determined at level of 1/2 threshold limit values (TLVs) recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). It is recommended that sampling rate of the passive samplers be obtained at site by measuring concentrations using both the NIOSH Method and passive samplers simultaneously. 3. When the passive samplers, which collected organic vapors, were exposed to clean air for five hours, there was no significant loss of organic vapors due to reverse diffusion. 4. When samples were stored at room temperature ($21.8{\pm}0.7^{\circ}C$) and refrigerator ($3.8{\pm}0.7^{\circ}C$), there was no significant difference in the accuracy of results. For trichloroethylene and n-hexane, accuracies were within 25 % at both temperatures until seven days. However, poor accuracy exceeding 25 % was indicated in toluene from the first day. It is recommended that samples be stored at freezing temperature below $0^{\circ}C$. 5. Sampling efficiency was significantly affected by direction of the passive samplers. Results of samplers facing wind and down, respectively, were compared. Lower amount of organic vapors were collected when the sampler was oriented down. It is recommended that, when air velocity is low in plants, the passive samplers be oriented to the wind. However, when air velocity is high, the passive samplers be oriented down.

This study was performed to evaluate the performance of three passive samplers made in U.S.A. Three passive samplers selected for this study included products made by 3M, Gilian, and SKC in U.S.A. Three organic solvents, such as toluene, trichloroethylene, and n-hexane which are used frequently in Korean industry were selected for the study. Conclusions obtained from this study are summarized as follows. 1. For toluene and trichloroethylene, the overall accuracy of the results from all of three products was within 25 %, which is the criteria recommended by the U.S. National Institute for Occupational Safety and Health (NIOSH). For n-hexane, the overall accuracy of the results from two products except 3M was exceeding 25 %. Thus 3M product showed the best accuracy among three products. 2. When passive samplers collected organic vapors were exposed to clean air for two hours, there were 12 - 16 % loss of organic vapors due to reverse diffusion in Gilian products. There was no significant loss in results from other two products. 3. Air velocity affected greatly on the performance of passive samplers which did not have permeation membrane. At high velocity, 100 cm/sec, accuracies of results from Gilian and SKC were 57 - 108 and 128 - 164 %, respectively. However, the results from 3M samplers, which contain permeation membrane, indicated accuracy below 25 %. 4. When passive samplers collected organic vapors for eight hours, the accuracy was reduced. Thus, it is recommended that passive samplers be used for less than four hours.

This study was designed to investigate effects of relative humidity on the breakthrough of charcoal tubes at a fixed vapor concentration and sampling time during mixed organic vapor sampling. A vapor generator was used to generate three different concentrations of mixed organic vapor and a stainless steel chamber was fabricated and utilized to maintain three different percentages of relative humidity while maintaining a constant temperature. The results were as follows; 1. At high relative humidity, breakthrough of mixed organic vapor occurred quickly at low vapor concentration than at high vapor concentration because of the reduced adsorption volume of charcoal tube due to humidity. 2. Breakthrough by competitive adsorption of vapors onto charcoal tube was observed at first from n-hexane having the lowest boiling point and highest vapor pressure among the three organic vapors investigated, followed by TCE. No breakthrough was observed from toluene under all experimental conditions. 3. For n-hexane, breakthrough was observed after 2 hours of sampling and breakthrough rates were increased as relative humidity increased. For TCE, breakthrough was found after 3 hours of sampling and breakthrough rates by sampling time were increased as vapor concentration increased. 4. The adsorbed amount of mixed organic vapor at breakthrough was shown to have statistically significant correlations with sampling time, relative humidity, and vapor concentration in descending order of correlation. Relative humidity and sampling time for n-hexane and sampling time and concentration for TCE were both statistically significantly correlated. 5. Relative humidity was found to affect the amount of breakthrough of mixed organic vapor and n-hexane. Among three percentages of relative humidity investigated, the amount of breakthrough at 85 % relative humidity was significantly larger than those of at lower percentages of relative humidity. No statistically significant difference was found between 25 % and 55 % relative humidity. 6. The results of multiple regression analysis between breakthrough and relative humidity, vapor concentrations showed that the coefficient of determination of mixed organic vapor was 0.263 and those of n-hexane and TCE were 0.275 and 0.189, respectively. 7. Flow rates of sampling pumps used were found to be affected by relative humidity present. At 25 %, 55 %, and 85 % relative humidity, the relative errors of sampling pump were 1.4 %, 13.4 %, and 18.6 %, respectively. In conclusion, the results of this study showed that high relative humidity could reduce the adsorption volume of charcoal tubes and subsequently increase breakthrough rates. Therefore, to prevent breakthrough when sampling mixed organic vapors, it is suggested that either sampling volume be reduced on the flow rate be lowered so as to minimize breakthrough of the most volatile organic vapor in the mixture. In addition, since the flow rates of a sampling pump can be adversely affected by high relative humidity, it is recommended to use a constant flow mode pump when sampling in the highly humid environment.

After oral administration of 14C-labelled $N^G$-mono[methyl-14C]-L-arginine into rats, 38.2 % and 14.7 % of the administered radioactivity bad been recovered in the urine and stool during 10 days. In the urine, 59.4 % of the radioactivity was recovered in the first 24-hours and used for the indentification of the formation of methylamine. The strong cation-exchange resin column chromatography showed 6.3 %, 7.4 %, 4.9 %, and 81.5 % of the distributions of radioactivity of the neutral, monomethylamine, basic, and uneluted portions, respectively. The radioactivity of monomethylamine portion reeluted into the column chromatography was 39.5 %. The radioactivities corresponding monomethylamine in the column chromatography, thin-layer chromatography, and thin-layer electrophoresis were 39.5 %, 37.3 %, and 28.8 % of the recovered radioactivity, respectively.

During the 1990s the workplace has grown more complex and business competition has increased world-wide. All organizations, whether for-profit or non-profit have been forced to respond to market changes. More advanced information and technology, greater product diversity, shorter product life cycles, increased quality requirements, more regulation oversight, decreasing productivity, more competitors, and increasing overhead costs have motivated organizations to focus on ways to deliver products cheaper, better, and faster. Many organizations are searching for ways to reduce costs through downsizing, reengineering business processes, implementing quality management, outsourcing, and improving cost management. Support departments that provide services internal to an organization such as human resources, legal, and environmental, safety, and health (ES&H) are often the first organization targeted for cost reduction and cost control initiatives because these functions are part of a rapidly increasing overhead cost. Recently, ES&H functions are incresingly being integrated into the business of business to contribute value to organization beyond mere compliance with ES&H regulations. The discussions and development of the ISO compatible Environmental Management Standards or Occupational Safety and Health Management Standards is another impetus to integrate ES&H function into the business of business. Thus, ES&H professional need new skills to analyze the cost of their function and communicate the value of the products and services they provide. In recent years, the need for and the importance developing cost management and business skills by ES&H professionals have been emphasized in the literature. Communicating with decision makers in terms of cost and value to the organization, and by using business language and business arguments is the first step toward effectively integrating ES&H activities into the business of business. Activity-based costing (ABC) is a cost management method that measures the cost of a product or service based on the actual use of resources by activities, and based on the actual amount of activities used to produce a product or service. ABC is recommended as a tool for managers of ES&H organizations to determine the cost of developing and providing ES&H products within a for-profit firm or non-profit agency. This paper discusses the trend of integration of ES&H functions into the mainstream of business activities within an organization. The general principles of treditional cost accounting are presented as a bases for understandging why and how ABC will provide more accurate estimates of cost. The principles and concepts of ABS are presented as a tool for determining more accurately the true cost of ES&H products and services.

Benzidine is recognized as a urinary bladder carcinogen in humans. The use of benzidine in industries was prohibited because of its carcinogenecity, but, production and usage of benzidine-based dye was still permitted in most countries. This study was performed to compare the excretory patterns of urinary metabolites between benzidine-based dye(Direct Black 38) and benzidine in rats Benzidine-based dye was administered orally at the doses of 0.3, 0.5, 0.7 mmol/kg and benzidine was administered orally at the doses of 0.2, 0.4, 0.6 mmol/kg into Sprague-Dawley rats. To analyze benzidine and its metabolites, the high performance liquid chromatography with an electric chemical and ultraviolet detector were used. N-acetylbenzidine, N,N'-diacetylbenzidine and 4-aminobiphenyl were identified in the urine of the rats receiving dye and benzidine. The excreted amount of the urinary benzidine from dye was almost 1/10 of that from benzidine. Excretion rates of metabolites were more prolonged in the dye receiving group than those of the benzidine group. Peak concentration time of urinary N,N'-diacetylbenzidine was more prolonged than other metabolites in both groups. The excreted amount of N-acetylbenzidine was more than the others in both group. These results suggested that N-acetylbenzidine may be an useful Biological exposure index for benzidine-based dye.