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Journal of Exposure Analysis and Environmental Epidemiology (2004) 14, 551–557 r 2004 Nature Publishing Group All rights reserved 1053-4245/04/$30.00

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Combined exposure to carbon disulfide and sulfuric acid simultaneously increases the risk of hand dermatitis in rayon industry TZU-CHIEH CHOU,a,b HAMM-MIN SHEU,c JING-ER CHIU,d JYUN-DE WU,e TUNG-SHENG SHIHf AND HO-YUAN CHANGa a Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road., Tainan 70428, Taiwan, Republic of China b Institute of Basic Medical Sciences, National Cheng Kung University, 138 Sheng-Li Road, Tainan 704, Taiwan, Republic of China c Department of Dermatology, National Cheng Kung University, 138 Sheng-Li Rd., Tainan 704, Taiwan, Republic of China d Department of Industrial Engineering and Management, National Yunlin University of Science and Technology, 123 University Road., Section 3 Touliu, Yunlin, Taiwan, Republic of China e Department of Occupational Safety and Health, Chang Jung Christian University, Kway Jen, Tainan, Taiwan, Republic of China f Institute of Occupational Safety and Health, Council of Labor Affairs, No. 99 Lane 407, Heng-Ke Road., Shijr City, Taipei, Taiwan, Republic of China

Objective: To evaluate the association between hand dermatitis (HD) and occupational exposure to CS2 and to determine whether combined exposure to CS2 and H2SO4 exhibits a higher risk of HD. Methods: In all, 110 subjects from a rayon factory were recruited and their exposure was classified into CS2 exclusively, H2SO4 exclusively, combined exposure, and nonexposure control based on workers’ job characteristics. A dermatologist was designated in the diagnosis of HD on palm and dorsal sites for each subject. Other confounding factors including detergent, glove wearing, and participation in wet work were determined using a person-to-person questionnaire interview from 37 randomly selected subjects. Results: Significant elevated odds ratios (ORs) for HD were found in CS2 exclusively (44.8, Po0.01) and combined exposure (49.0, Po0.001) compared with control. Dose–response trends of ORs for HD were found across control, single exposure, and combined exposure for both CS2 and H2SO4. Conclusions: HD could occur resulting from occupational exposure to CS2 alone. This study was unable to affirm that the exposure to H2SO4 alone is associated with HD due to limited H2SO4 exposure subjects. The combined exposure to both CS2 and H2SO4 simultaneously could increase the risk of HD. The control remedy in preventing dermal contact with either CS2 or H2SO4 among the rayon workers should be performed immediately. Journal of Exposure Analysis and Environmental Epidemiology (2004) 14, 551–557. doi:10.1038/sj.jea.7500385 Published online 28 July 2004

Keywords: dose–response, carbon disulfide, sulfuric acid, combined exposure, rayon industry, hand dermatitis.

Introduction The humans are very rarely exposed to only a single chemical in the general environment as well as in the most occupational settings (Feron et al., 2002). The contemporary regulations and risk assessment with respect to most environmental or occupational pollutants are, however, still on single-compound basis because the framework of scientific basis and methodology in exploring the health effects of the mixture exposure is mostly still under development. Thus, overestimation or underestimation of toxicity from singleexposure basis to a mixture-exposure basis can occur depending on toxicokinetic and toxicodynamic interactions Address all correspondence to: Dr. Ho-Yuan Chang, Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University Medical College, 138 Sheng-Li Road, Tainan 70428, Taiwan, ROC. Tel.: þ 886-6-2378754; Fax: þ 886-6-274-3748. E-mail: [email protected] Received 1 June 2003; accepted 3 April 2004; published online 28 July 2004

(Calabrese, 1991). In general occupational environment, the employees are commonly exposed to diversified chemicals such as detergents, acids, alkalis, water, as well as organic solvents, simultaneously. Most of them are the common factors causing irritant contact dermatitis, one of the most prevalent skin diseases in occupational medicine (Wigger-Alberti and Elsner, 1999). On the other hand, skin diseases have long been considered as the most prevalent diseases in occupational environments. In Germany, occupational skin diseases account for 34% of all registered occupational diseases (Diepgen and Coenraads, 1999). Other investigators in the world estimated the proportions of skin diseases at about 9–35% among all occupational diseases (Vaaranen et al., 1984; Central Bureau of Statistics, 1985; Mathias and Morrison, 1988). Some organic solvents have been documented to cause skin irritation in occupational environments (Wahlbert and Adams, 1999). McCurdy et al. (1995) found a significant dose–response pattern of dermatitis to methanol and isopropanol in semiconductor workers. 2-Butoxyethanol and isopropoxyethanol have demonstrated their capabilities to cause skin irritation in animal studies (Zissu, 1995). The

CS2/H2SO4 vs. hand dermatitis

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employees in the workplace could suffer contact dermatitis with repeated exposure to solvents. The workers occupationally exposed to kerosene, one of the lubricating oils frequently used in industry, in a ball-bearing factory were found to have an elevated rate of contact dermatitis (Jee et al., 1986). Owing to their ubiquity in the general occupational milieu, organic solvents are of concerns in occupational skin diseases. Carbon disulfide (CS2) has been widely used as a soil disinfectant, an extracting solvent in the general chemical analysis, and in the manufacturing processes of carbon tetrachloride, viscose rayon fibres, and cellophane (ATSDR, 1996). However, very limited studies have evaluated its skin irritating potency. Acids are also commonly used in chemical industries. Overdose exposure to such chemicals could cause chemical burns, consequently, inducing dermatitis or aggravating the dermatoses (Frosch, 1992; Ang et al., 2001) possibly via protein denaturalization, cytotoxicity to the skin, and cell necrosis following chemical burns (Mathias, 1988; Elsner, 1994). Hydrofuric acid, hydrochloric acid, and orthophosphoric acid have been reported as skin hazards in the semiconductor industry (Fujimoto, 1999). However, very few statistics or epidemiological studies have reported the dermatitis resulting from occupational exposure to such inorganic acids. Wigger-Alberti et al. (2000) have demonstrated that the sequential exposure to sodium lauryl sulfate (SLS) and toluene could affect the skin irritation. They found the pretreatment with SLS caused an increasing susceptibility to toluene on skin irritation and vice versa. The employees in the occupational setting are very likely exposed to more than a single skin hazard. It is possible that the skin irritating potency of a chemical could be underestimated if the combined exposure to the chemical of interest and other concurrent chemicals poses higher toxicity on skin than single exposure in the occupational settings. The workers in a rayon factory could be possibly exposed to CS2 exclusively, or H2SO4 exclusively, or combined exposure simultaneously during the manufacturing processes. Rayon manufacturing has been documented as one of the high-risk occupational groups for CS2 exposure (Cox et al., 1998; Chang et al., 2002; Luo et al., 2003; Shih et al., 2003). Drexler et al. (1995) reported that the total body uptake of CS2 exposure was elevated for those who have pathological skin conditions. The prevalences of dermatoses were found as 20% and 28% for all subjects and spinning workers, respectively. H2SO4 is another raw material primarily used in the prespinning process of the rayon manufacturing. However, no any studies have been conducted on hand dermatitis (HD) associated with the exposure to H2SO4. As the onset time is easily missed due to very mild symptom in the beginning of dermatitis (Frosch, 1992) and also approximately 50% of patients have periodic occurrences of the occupational dermatitis (Marks et al., 2002), 552

prevalence is more feasible than incidence in the epidemiological studies regarding occupational dermatitis. Therefore, the aims of this study were to evaluate the association between HD and occupational exposure to CS2 and to determine whether the combined exposure to both CS2 and H2SO4 simultaneously causes elevated risk of HD among rayon-manufacturing workers.

Subjects and methods Study Population The study subjects were recruited in a rayon factory located in mid-Taiwan. The workers in the rayon factory were grouped into eight departments: viscose-producing, viscosestorage, prespinning, spinning, cellophane-producing, post-treatment, packing, and administration. In the viscoseproducing department, cellulose is generated from wood pulp after treatment. After the addition of pure CS2 liquid in churns in an open chamber, cellulose is converted into cellulose xanthate. The cellulose xanthate is then transformed to yield a viscose solution in the viscose-storage department. The viscose solution is sampled via the viscose tank orifice periodically with a frequency of every 40-min interval and is then analyzed to assure the appropriate ratio of the cellulose xanthate to CS2 in this process. In the prespinning department, zinc sulfate (ZnSO4) is added into sulfuric acid (H2SO4) to produce a sulfur-containing acidic solution. H2SO4 concentration in the solution decreases gradually to about 20% during this process. The sulfur-containing acidic solution is sampled via a tank orifice periodically, similar in viscose solution check-up procedure, for further quality assurance analysis in every 40 min. The viscose solution is pumped through a platinum nozzle into a warm H2SO4 bath at very high speed. Via neutralization of alkaline-based viscose solution with acid-based sulfur-containing solution, a continuous thread is made from this mixture in the spinning department. As CS2 is released when viscose reacts with the diluted H2SO4 solution (H2SO4 ¼ 10%), thread spinning is implemented within an exhaust-ventilation-equipped hood. The thread is then transferred to the post-treatment department by cart. The rayon thread is washed several times in the post-treatment department. It is then packed in the packing department. Cellophane, a kind of plastic paper, is another product made from viscose in the cellophaneproducing department. Based on the information provided by the foreman and our intensive observation in field study, the workers in each department were classified into four different exposure categories according to the possibility and frequency their hands and forehands exposed to CS2 and/or H2SO4. The workers in the viscose-producing and viscose-storage departments are exposed to pure CS2 liquid on their hands during the production of cellulose xanthate and viscose solution as Journal of Exposure Analysis and Environmental Epidemiology (2004) 14(7)


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well as the quality check-up of CS2-containing solution 6–8 times in a work shift. These workers were classified as CS2 exclusively because they are only exposed to CS2 and are unlikely exposed to any H2SO4 (n ¼ 13) (Table 1). Similarly, the workers in the prespinning department, easily exposed to H2SO4 (about 20%, at least 6–8 times a day) and exposed to no CS2, were classified as H2SO4 exclusively (n ¼ 2). The workers in the spinning, cellophane-producing, and posttreatment departments, exposed to the solution containing saturate aqueous CS2 ( ¼ 2.2 g/l) and diluted H2SO4 ( ¼ 10%) simultaneously, were classified as combined exposure group (n ¼ 66). The workers in the packing and administration departments had few opportunities to get exposed to either chemical of interest and were defined as control (n ¼ 29). Therefore, 79 workers either exposed to CS2 exclusively (n ¼ 13) or combined with H2SO4 exposure (n ¼ 66) were classified as CS2 in general. Similarly, 68 workers either exposed to H2SO4 exclusively (n ¼ 2) or combined with CS2 exposure (n ¼ 66) were classified as H2SO4 in general. All subjects were male. Their average age was 38.7 years (SD ¼ 12.8, ranging from 21 to 60) and they worked for 12.7 years (SD ¼ 13.1, ranging from 1 to 44). The distributions of their age and employment duration were rather widely spread among four groups and no significant differences were found between any exposed groups. Their interdepartmental job rotations were very rare because their job training was primarily based on apprenticeship.

Other Confounding or Modifying Variables This study was designed to examine the effects of CS2 and H2SO4 exposure on HD. Other factors that potentially affected this relationship such as the use of detergent, gloves, and wet work were included in a package of long-listed questions designed for a nationwide survey purpose. As person-to-person questionnaire interview was considerably timedemanding, only 37 study subjects randomly selected from the 110 study subjects were performed. The subjects were asked to answer how frequently (never, only before going home, or more than three times a day) and in what manner (never, tap water only, or soap and/or detergent)

they washed their hands and whether they wore protective gloves (never, only when repairing a machine, about half the time, often, or always while working).

HD Examination The worker’s hands on both palm and dorsal sides were selected as the examination sites because they are most likely to get exposed to manufacturing liquids. A dermatologist from a medical center was designated to examine of aforementioned skin sites for each participant. HD was defined when the skins exhibited a clear eczematous picture of erythema, papules, vesicles, and fissures (Vermeulen et al., 2001). Data Analysis The exposure to CS2 and/or H2SO4 as well as HD was recorded as dichotomous variables (yes/no). The odds ratio (OR) was calculated to estimate the relative risk of developing HD among various exposure conditions. The 95% confidence interval (95% CI) of the OR was used to evaluate whether the risk was significant. JMP (release 3.2.6, SAS Institute Inc., NC, USA) was used throughout the statistical analyses. Mantel-extension w2 for trend was used to test whether the dose–response of HD across control, single exposure, and combined exposure for CS2 and H2SO4 followed a trend fashion. Only HD on either the palm or dorsal area of the hands was estimated.

Results The descriptive information collected from questionnaire with respect to the hand washing habit, the usage of detergents, and the glove wearing among the randomly selected workers is shown in Table 2. About 90% (81.8– 100.0%) of the examined subjects washed their hands more than three times a day. The frequency for the use of detergents (soap and/or detergent) was found nil (0.0%) in CS2 and/or H2SO4 exposure groups, less than in control group (14.3%). Glove wearing status was more frequent in

Table 1. The number of the subjects in each exposure classification based on their possibility and frequency in the exposure to either CS2 and/or H2SO4. CS2 exposure status

H2SO4 exposure status Possibly exposed to H2SO4 Unlikely exposed to H2SO4 Subtotal

Possibly exposed to CS2

Unlikely exposed to CS2

Subtotal

Combined exposure (n ¼ 66)a CS2 exclusively (n ¼ 13) CS2 in general (n ¼ 79)c

H2SO4 exclusively (n ¼ 2) None-exposure control (n ¼ 29) (n ¼ 31)

H2SO4 in general (n ¼ 68)b (n ¼ 42) (n ¼ 110)

a

Combined exposure: exposed to both CS2 and H2SO4 simultaneously. H2SO4 in general: subjects exposed to either H2SO4 exclusively or to CS2 + H2SO4 simultaneously. c CS2 in general: subjects exposed to either CS2 exclusively or to CS2+H2SO4 simultaneously. b

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554 Chou et al.

Table 2. The descriptive information with respect to other factors potentially affecting the relations of HD to CS2 and/or H2SO4 collected by questionnaire from 37 randomly selected study subjects by person-to-person interview. Exposure statuses Questions

Specific items

Control n

CS2 exclusively

Combined exposurea

CS2 in generala

H2SO4 in generala

Total

(%)

n

(%)

n

(%)

n

(%)

n

(%)

n

(%)

9 2

(81.8) (18.2)

1 0

(100.0) (0.0)

16 2

(88.9) (11.1)

25 4

(86.2) (13.8)

17 2

(89.5) (10.5)

33 4

(89.2) (10.8)

0 (0.0) 0 7 (100.0) 11

(0.0) (100.0)

0 1

(0.0) (100.0)

0 18

(0.0) (100.0)

0 29

(0.0) (100.0)

0 19

(0.0) (100.0)

0 (0.0) 37 (100.0)

The measure of hand washing Soap and/or detergent Tap water Never Subtotal

1 (14.3) 0 6 (85.7) 10 0 (0.0) 1 7 (100.0) 11

(0.0) (90.9) (9.1) (100.0)

0 1 0 1

(0.0) (100.0) (0.0) (100.0)

0 11 7 18

(0.0) (61.1) (38.9) (100.0)

0 21 8 29

(0.0) (72.4) (27.6) (100.0)

0 12 7 19

(0.0) (63.2) (36.8) (100.0)

1 (2.7) 28 (75.7) 8 (21.6) 37 (100.0)

Glove

0 1

8 0

(72.7) (0.0)

1 0

(100.0) (0.0)

6 3

(33.3) (16.7)

14 3

(48.3) (10.3)

7 3

(36.8) (15.8)

0 (0.0) 0 1 (14.3) 2 5 (71.4) 1 7 (100.0) 11

(0.0) (18.2) (9.1) (100.0)

0 0 0 1

(0.0) (0.0) (0.0) (100.0)

2 2 5 18

(11.1) (11.1) (27.8) (100.0)

2 4 6 29

(6.9) (13.8) (20.7) (100.0)

2 2 5 19

(10.5) (10.5) (26.3) (100.0)

Hand washing habit

Often Always throughout the working hours About half chances to wear Only wear during repair Never Subtotal

7 (100.0) 0 (0.0)

(0.0) (14.3)

15 4

(40.5) (10.8)

2 (5.4) 5 (13.5) 11 (29.7) 37 (100.0)

n: number of subjects. Combined exposure: exposed to both CS2 and H2SO4 simultaneously; CS2 in general: subjects exposed to either CS2 exclusively or to CS2+H2SO4 simultaneously; H2SO4 in general: subjects exposed to either H2SO4 exclusively or to CS2+H2SO4 simultaneously.

a



More than three times a day Only washing hands before going home Never Subtotal

(%)

n

H2SO4 exclusively


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CS2 and/or H2SO4 exposure groups than in the control group. The gloves were half-sleeve long, however, based on the intensive field observation, not effective enough to prevent the spillage of CS2 and/or H2SO4 into the gloves from manufacturing liquids. A higher prevalence on palm than on dorsal hand areas was observed in HD for all exposed groups (Table 3). The prevalence rates of HD on dorsal hand sites were 7.7%, 0.0%, and 6.1%, respectively, for CS2 exclusively, H2SO4 exclusively, and combined exposure groups. Alarmingly high prevalence rates of HD were found on palm sites ranging from 50.0% to 63.6% for the three different situations of CS2 and/or H2SO4 exposure groups. Only 3.4% was found for the control group in HD. HD on dorsal site was excluded from further analyses due to their remarkably low prevalence rates compared with palm site. Significantly elevated OR for HD was found in CS2 exclusively group (OR ¼ 44.8, 95% CI ¼ 6.4–933.7), suggesting that CS2 could be an effective Table 3. The prevalence of HD on dorsal and palm hands categorized by various exposure conditions. Anatomical site Skin exposure to chemical

HD n

Case no. Prevalence (%)

Dorsal

Control 29 13 CS2 exclusively H2SO4 exclusively 2 Combined exposurea 66 Subtotal 110

0 1 0 4 5

0.0 7.7 0.0 6.1 4.5

Palm

Control 29 1 CS2 exclusively 13 8 H2SO4 exclusively 2 1 Combined exposurea 66 42 Subtotal 110 52

3.4 61.5 50.0 63.6 47.3

n: number of subjects. Combined exposure: exposed to both CS2 and H2SO4 simultaneously.

a

skin irritant in the occupational environments. Significantly elevated OR was also found in combined exposure group (OR ¼ 49.0, 95% CI ¼ 9.5–900.6), but not in H2SO4 exclusively group (OR ¼ 28.0, 95% CI ¼ 0.8–1428.7). Moreover, significantly increasing trends (Po0.01–0.001) of the ORs for HD were found among control, single exposure, and combined exposure for either CS2 or H2SO4 (Table 4).

Discussion Contact dermatitis most frequently results from repeated, direct skin contact with organic solvents rather than just an occasional short-term exposure (Mathias, 1988). Due to its considerably low boiling point of 46.51C, Pirila et al. (1971) proposed that CS2 was one of the top 10 organic solvents capable of causing skin irritation. However, no data either in animal tests or human epidemiological studies have supported this hypothesis yet. The finding of significantly elevated OR for HD in CS2 exclusively group (OR ¼ 44.8, 95% CI ¼ 6.4–933.7) shown in this study (Table 4) is the first human study to date to affirm that CS2 could be a potent skin irritant. The irritant action of CS2 could result primarily on skin surface, stratum corneum, and cell membrane lipid dissolution, as proposed by Elsner (1994). Mixture exposure like organic solvents and acids are commonly present in occupational environments simultaneously. The skin diseases resulting from simultaneous exposure to both organic solvents and inorganic acids in humans, however, have not yet been elucidated. In this study, the workers were classified as nonexposure, single exposure, and combined exposure based on the probability of chemical contact they were exposed to in the job. In comparison with combined exposure group, the workers in CS2 exclusively group were dermally exposed to higher CS2 because they were involved with pure CS2 liquid with the frequency of 6–8 times per work shift. However, a slightly

Table 4. ORs for HD and dose–response trend tests across the nonexposure control, single-exposure exclusively (CS2 or H2SO4), and combined exposure (CS2+H2SO4). ORs (95% CI)

n HD Trend for control, CS2 exclusive, and combined exposure Trend for control, H2SO4 exclusive, and combined exposure

Control

CS2 exclusively

H2SO4 exclusively

Combined exposure

29 1.0

13 44.8 (6.4–933.7)**

2 28.0 (0.8–1428.7)*

66 49.0 (9.5-900.6)***

P-valuea

o0.01 o0.001

n: number of subjects. a by Mantel-extension w2 for trend. *Po0.05. **Po0.01. ***Po0.001.


555


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higher OR for HD was found in combined exposure group (OR ¼ 49.0) than in CS2 exclusively group (OR ¼ 44.8) shown in Table 4 suggesting that coexposure to H2SO4 poses substantial risk of CS2-inducing HD. Similarly, the H2SO4 exclusively group were exposed to pure or concentrate H2SO4 solution (H2SO4 ¼ 20%), whereas, the combined exposure group were only exposed to less concentrate H2SO4 ( ¼ 10%) in the work. Significantly elevated OR of HD in combined exposure group (OR ¼ 49.0) comparing with in H2SO4 exclusively (OR ¼ 28.0) also suggested that coexposure to CS2 contributes a significant HD risk H2SO4-causing HD (Table 4). Taken together, these findings suggested the workers with the combined exposure to CS2 and H2SO4 simultaneously might exert greater risks of HD than those with either single exposure. Previous studies in exploring relations of HD to either organic solvents or acids were only single-chemical oriented (Jee et al., 1986; Catanzaro and Smith, 1991; Sato et al., 1996; Iliev et al., 1997; Gottlober et al., 2001). As mentioned previously, most of the occupational settings are, in fact, mixture exposure, like the case presented in this study. If this study was designed in single-chemical basis, the ORs for HD were 48.3 (9.5–882.7), and 48.2 (9.4–884.3), for CS2 and H2SO4 exposure, respectively (Table 5). Compared with the findings derived by the combined-exposure oriented (Table 4 vs. Table 5), we found similar conclusions drawn for CS2 exposure (ORs ¼ 44.8 vs. 48.3, Po0.01 vs. Po0.001) but different conclusions for H2SO4 (ORs ¼ 28.0 vs. 48.2, P40.05 vs. Po0.001). In a single-chemical-based study design, 79 subjects were classified in the group of CS2 in general (Table 5). However, among them, 66 subjects (66/ 79 ¼ 84%) should be classified as the combined exposure in combined-exposure-based study (Table 4). Similarly, about 97% subjects (66/68) were erroneously classified into the group of H2SO4 in general from the group of the combined exposure, suggesting why the conclusions regarding HD for

Table 5. Prevalence rates and ORs of HD on control, CS2 in general, and H2SO4 in general on a single-chemical-based study design. Skin exposure to chemical

Control CS2 in generala H2SO4 in generala

HD n

Case no.

Prevalence (%)

ORs (95% CI)*

29 79 68

1 50 43

3.4 63.3 63.2

1.0 (F)** 48.3 (9.5–882.7)*** 48.2 (9.4–884.3)***

n: number of subjects. a CS2 in general: subjects exposed to either CS2 exclusively or to CS2+H2SO4; H2SO4 in general: subjects exposed to either H2SO4 exclusively or to CS2+H2SO4. *Po0.05. **Po0.01. ***Po0.001.

556

H2SO4 exposure were inconsistent between two study designs. Most importantly, the significant increase of HD in combined exposure to CS2 and H2SO4 compared with in any single exposure could not be found from the singlechemical-oriented design. Sun et al. (1995) conducted a study to estimate the occupational HD prevalence among all patients (n ¼ 164) in Taiwan. They found that the prevalence of occupational contact dermatitis on the hands was high (94.8% and 86.5% on right and left hand, respectively), indicating the importance of the hands in occupational contact dermatitis studies. The workers in the departments of prespinning, viscoseproducing, viscose-storage, spinning, post-treatment, and cellophane-producing are inevitable to use their bare hands to perform the manufacturing rayon, consequently, their hands are easily exposed to rayon-related chemicals, that is, CS2 and H2SO4. The findings identifying the palms of the hands as the most vulnerable sites in this study were consistent with our field investigation that about 40% of the workers did not wear protective gloves during working hours, discovered during the questionnaire interview with selected workers (Table 2). The enforcement of worker’s wearing impermeable gloves during rayon-manufacturing process is strongly recommended. This investigation showed a considerably high prevalence (over 40%) of occupational contact dermatitis on the hands of rayon-manufacturing workers. This was substantially higher than the 11.0% of all identified dermatitis patients in the chemical industry by Sun et al. (1995). This was also higher than the prevalence of 22.5% for occupational skin diseases from occupational solvent exposure by Goon and Goh (2000). Occupational exposure to detergents, occlusive glove use and wet work found in previous studies accounted for only 12.7%, 6.2%, and 11.1% of the prevalence rates of contact dermatitis, respectively (Cherry et al., 2000). These potential confounding factors are not able to account for the significantly higher prevalence of occupational contact dermatitis on hands in this study. Moreover, the workers in all kinds of exposed groups had few chances to be exposed to soap and/or detergent (Table 2) and the workers did not use any latex gloves (data not shown). These facts also help to exclude the confounding effects of high prevalence of the HD due to detergent and latex gloves. All of these emphasize that the skin problem in the rayon industry is a more serious issue than in other industries. Occupational skin problems might not only perturb the pathological conditions of the skin but also possibly enhance occupational toxicant absorption via the skin. Drexler et al. (1995) demonstrated that the total body burden of CS2 was significantly greater in the workers with skin diseases or skin irritations than the workers with healthy skin. Understanding the skin disease status for occupational workers is important with respect to preventing the resulting systematic toxicity as well as skin diseases. The alarmingly high prevalence of Journal of Exposure Analysis and Environmental Epidemiology (2004) 14(7)


occupational contact dermatitis on the palms of the hands presented in this study warrants an effective control remedy in preventing dermal contact with either CS2 or H2SO4 among the rayon workers. The findings also warrant further researches on exploring the relationship between CS2- and/or H2SO4-related diseases to various skin conditions in the rayon industry. In summary, we concluded that HD could occur resulting from occupational exposure to CS2 alone. We were unable to affirm that the exposure to H2SO4 alone is associated with HD due to limited H2SO4 exposure subjects. People exposed to both CS2 and H2SO4 simultaneously could be at a higher risk of HD. The control remedy in preventing dermal contact with either CS2 or H2SO4 among the rayon workers should be executed with the highest priority.

Acknowledgements This study was jointly supported by the National Science Council (Grant Number: NSC-91-2320-B-285A-001) and the Institute of Occupational Safety and Health, Council of Labor Affairs (Grant number: IOSH89-A307), Taiwan. The authors sincerely thank the workers and employers of the rayon factory for their participation and cooperation.

References Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Carbon Disufide. US Public Health Service, US Department of Health and Human Services, Virginia, National Technical Information Services, Virginia, 1996. Ang P., Chua S.H., and Gan S.L., et al. Allergens and irritants. In: Ng S.K., and Goh C.L. (Eds.). The Principles and Practice of Contact and Occupational Dermatology in the Asia-Pacific Region. World Scientific, New Jersey, 2001, pp. 74–116. Calabrese E.J. Multiple Chemical Interactions. Lewis Publishers, Chelsea, MI, USA, 1991. Catanzaro J.M., and Smith Jr. J.G. Propylene glycol dermatitis. J Am Acad Dermatol 1991: 24: 90–95. Central Bureau of Statistics. Statistics of Occupational Accidents. Staatsuitgeverij, The Hague, 1985. Chang H.Y., Chou T.C., Wang P.Y., and Shih T.S. Biological monitoring of occupational exposure to carbon disulfide: focus on the kinetics of urinary TTCA by continuous urine collection among rayon factory workers. Toxicol Ind Health 2002: 18: 1–14. Cherry N., Meyer J.D., and Adisesh A., et al. Surveillance of occupational skin disease: EPIDERM and OPRA. Br J Dermatol 2000: 142: 1128–1134. Cox C., Hee S.S., and Tolos W.P. Biological monitoring of workers exposed to carbon disulfide. Am J Ind Med 1998: 33: 48–54. Diepgen T.L., and Coenraads P.J. The epidemiology of occupational contact dermatitis. Int Arch Occup Environ Health 1999: 72: 496–506. Drexler H., Goen T., and Angerer J. Carbon disulphide. II. Investigations on the uptake of CS2 and the excretion of its metabolite 2-thiothiazolidine-4-


Chou et al.

carboxylic acid after occupational exposure. Int Arch Occup Environ Health 1995: 67: 5–10. Elsner P. Irritant dermatitis in the workplace. Dermatol Clin 1994: 12: 461–467. Feron V.J., Cassee F.R., Groten J.P., vanVliet P.W., and van Zorge J.A. International issues on human health effects of exposure to chemical mixtures. Environ Health Perspect 2002: 110(Suppl. 6): 893–899. Frosch P.J. Cutaneous irritation. In: Rycroft R.J.G., Menne T., Frosch P.J., et al. (Eds.). Textbook of Contact Dermatitis. Springer-Verlag, Berlin, 1992, pp. 28–61. Fujimoto G.R. Semiconductor industry. In: Adams R.M. (Ed.). Occupational Skin Disease. W.B. Saunders Company, Philadelphia, 1999, pp. 463–469. Goon A.T., and Goh C.L. Epidemiology of occupational skin disease in Singapore 1989–1998. Contact Dermatitis 2000: 43: 133–136. Gottlober P., Gall H., and Peter R.U. Allergic contact dermatitis from natural latex. Am J Contact Dermatitis 2001: 12(3): 135–138. Iliev D., Hinnen U., and Elsner P. Skin roughness is negatively correlated to irritation with DMSO, but not with NaOH and SLS. Exp Dermatol 1997: 6: 157–160. Jee S.H., Wang J.D., and Sun C.C., et al. Prevalence of probable kerosene dermatoses among ball-bearing factory workers. Scand J Work Environ Health 1986: 12: 61–65. Luo J.C., Chang H.Y., and Chang S.J., et al. Elevated triglyceride and decreased high density lipoprotein level in carbon disulfide workers in Taiwan. J Occup Environ Med 2003: 45: 73–78. Marks J.G., Elsner P., and DeLeo V. Contact and Occupational Dermatology. Mosby, Inc., London, 2002, pp. 323–338. Mathias C.G.T. Occupational dermatoses. In: Carl Z. (Ed.). Occupational Medicine. Year Book Medical Publishers, Inc., Chicago, 1988, pp. 132–165. Mathias C.G.T., and Morrison J.H. Occupational skin diseases, United States. Results from the Bureau of Labor Statistics Annual Survey of Occupational Injuries and Illnesses, 1973 through 1984, 1988: 124: 1519–1524. McCurdy S.A., Pocekay D., and Hammond S.K., et al. A cross-sectional survey of respiratory and general health outcomes among semiconductor industry workers. Am J Ind Med 1995: 28: 847–860. Pirila V., Fregert S., and Bandmann H.J., et al. Legislation on occupational dermatoses. Acta Dermato-Venereol 1971: 51: 141–145. Sato A., Obata K., and Ikeda Y., et al. Evaluation of human skin irritation by carboxylic acids, alcohols, esters and aldehydes, with nitrocellulosereplica method and closed patch testing. Contact Dermatitis 1996: 34: 12–16. Shih T.S., Chou T.C., and Chang H.Y., et al. Accumulation of urinary 2thiothiazolidine-4-carboxylic acid (TTCA) among the workers occupationally exposed to a-week-long exposure to carbon disulfide. Sci Total Environ 2003: 308(1–3): 37–47. Sun C.C., Guo Y.L., and Lin R.S. Occupational HD in a tertiary referral dermatology clinic in Taipei. Contact Dermatitis 1995: 33: 414–418. Vermeulen R., Kromhout H., and Bruynzeel D.P., et al. Dermal exposure, handwashing, and HD in the rubber manufacturing industry. Epidemiology 2001: 12: 350–354. Wigger-Alberti W., and Elsner P. Contact dermatitis due to irritation. In: Adams R.M. (Ed.). Occupational Skin Disease. W.B. Saunders Company, Philadelphia, 1999, pp. 1–22. Wigger-Alberti W., Krebs A., and Elsner P. Experimental irritant contact dermatitis due to cumulative epicutaneous exposure to sodium lauryl sulphate and toluene: single and concurrent application. Br J Dermatol 2000: 143: 551–556. Wahlbert J.E., and Adams R.M. Solvents. In: Adams R.M. (Ed.). Occupational Skin Disease. W.B. Saunders Company, Philadelphia, 1999, pp. 484–500. Zissu D. Experimental study of cutaneous tolerance to glycol ethers. Contact Dermatitis 1995: 32: 74–77.

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