Symptoms among workers with long-term exposure to methyl bromide. An epidemiological study.

Symptoms as an important sign of the effects of methyl bromide were studied in 56 male workers (37 currently exposed and 19 previously exposed) in a methyl bromide factory. The workers were 18 to 62 yr of age (mean age: 41) and were exposed from 1 to 25 yr (mean: 7 yr). They were compared to 56 age-matched referents with a standardized questionnaire. The results of pairwise comparison of the symptoms of the age-matched pairs of exposed and referent subjects showed that the occurrence of dizziness, numbness, paresthesia and weakness of extremities, nightmares, fatigue and dry and scaly skin was statistically significantly higher among the workers than among the referents. When the symptoms during the work shift (acute symptoms) were compared, irritation symptoms such as itching, bullae or reddish swollen hands and runny noses with nasal irritation were reported significantly more often in the exposed groups. The correlation of the symptoms among the exposed workers suggested that chronic symptoms are closely related to acute irritation symptoms and exposure duration. The results suggest that symptom inquiry is useful for detecting the possible effects of exposure to methyl bromide.     

Occupational exposure to mixtures of organic solvents increases the risk of neurological symptoms among printing workers in Hong Kong

LEARNING OBJECTIVES: Summarize the nature and extent of exposure to organic solvents to which printing workers in this study were subjected. Compare the numbers of neurological symptoms in exposed and non-exposed workers and how they related to level of exposure, as defined by specific job title or by air sampling. Clarify the relationship between exposure to organic solvents and individual psychoneurological and other symptoms. ABSTRACT: The health effects of low-dose occupational exposure to organic solvents remains unclear. A cross-sectional survey was conducted among 762 male printing workers to assess the impacts of exposure to mixtures of n-hexane, toluene, isopropyl alcohol, and benzene on neurological and other symptoms. After controlling for age, smoking, alcohol drinking, past exposure history, working hours and shift work, current exposure to solvent mixtures was significantly associated with the total number of neurological symptoms and with the prevalence of specific symptoms of the nervous system and mucous membrane irritation. The adjusted odds ratio of neurovegetative lability (1.7-5.9), abnormal or reduced smell (1.6-4.1), memory loss (1.8), and mucous membrane irritation symptoms (1.5-4.6) significantly increased in the exposed group, especially when the summation index of exposure exceeded one.     

Diffusive Sampling and Biological Monitoring of 2-Bromopropane

The possibilities to apply personal ambient air monitoring by diffusive sampling and biological exposure monitoring by urinalysis for 2-bromopropane or its metabolites were explored. The abilities of carbon cloth to adsorb 2-bromopropane was examined by experimental vapor exposure followed by solvent extraction and FID-GC. Urine from factory workers and rats exposed to 2-bromopropane were analyzed for 2-bromopropane, acetone and isopropyl alcohol by FID-GC, and for bromide ion by ECD-GC after chemical methylation. Carbon cloth adsorbed 2-bromopropane in a manner linearly related to exposures up to 1500 mg/m³ and to 8 h. The adsorption could quantitatively detect a 15 min peak exposure at 3,000 mg/m³. In rat experiments, analyses of urine samples collected over a 4-h period after termination of a 4-h exposure to 2-bromopropane at 500, 1,000 or 1,500 mg/m³ showed that acetone and bromide ion were excreted dose-dependently. Essentially, no 2-bromopropane or isopropyl alcohol was detected. When the analytical methods were applied to urine samples from 5 male workers exposed to 2-bromopropane at a low level (3 mg/m³ as a geometric mean), acetone and bromide ion levels were within respective normal ranges in four cases, but were higher than the upper limits of the normal ranges in the fifth case of a foreman who probably had the highest exposure. Thus, diffusive sampling is applicable to monitor exposure to 2-bromopropane. Urinalysis for acetone and bromide ion in combination appears to be a promising selective tool for biological monitoring of occupational exposure to 2-bromopropane. Received: 26 February 1996/Revised: 29 May 1996     

Perceived odor,irritation, and health symptoms following short-term exposure to acetone

The subjectivity of irritancy judgments can bias attempts to establish exposure guidelines that protect individuals from the sensory irritation produced by volatile chemicals. At low to moderate chemical concentrations, naive and occupationally exposed individuals often show considerable variation in the reported levels of perceived irritation. Such variation could result from differences in exposure history, differences in the perceived odor of a chemical, or differences in generalized response tendencies to report irritation, or response bias. Thus, experimental evaluation of sensory irritancy must dissociate sensory irritation from response bias. To this end, judgments of perceived irritation from 800 ppm acetone were obtained from acetone-exposed workers and age- and gender-matched naive controls. To assess the role of response bias during exposure to odorants, subjects were also exposed to phenylethyl alcohol (PEA), an odorant that does not produce sensory irritation. Following exposure, subjects completed a subjective symptom survey that included symptoms that have been associated with long-term solvent exposures and symptoms that have not. Acetone-exposed workers and naive controls reported large differences in the perceived intensity of odor and irritation from acetone, yet no differences in the perception of PEA. However, for both groups, the most significant factors mediating reported irritancy and health symptoms from acetone were the perceived intensity of its odor and an individual's bias to report irritation from PEA. The perception of odor intensity and degree of response bias will differ between and within groups of exposed and naive individuals; hence, an assessment of the influence of these factors in experimental and workplace studies of chemical irritancy is warranted. Am. J. Ind. Med. 31:558–569, 1997. © 1997 Wiley-Liss, Inc.     

Occupational health survey on workers exposed to 2-bromopropane at low concentrations

BACKGROUND: Recent case studies in Korea and animal studies revealed the reproductive and hematopoietic toxicity of 2-bromopropane introduced into workplaces as an alternative to ozone-layer depleting chlorofluorocarbons. We aimed to clarify the dose-effect relationship of 2-bromopropane in workers. METHOD: The exposure concentration of 2-bromopropane and hematological indices, hormonal levels, menstruation status, and sperm indices were examined in 25 workers (11 males, 14 females) at a 2-bromopropane factory. Regression analyses of the examined indices against time-weighted average (TWA) of exposure concentration were conducted. RESULTS: Amenorrhea or polymenorrhea was observed only in older females. Hematological indices had a significant relation with TWA of exposure concentration in females with normal menstruation. However, no other indices showed any significant relation with TWA of 2-bromopropane. CONCLUSIONS: No severe cases of reproductive or hematopoietic disorders were found at less than 10 ppm (TWA), but a possible adverse effect of 2-bromopropane on hematopoiesis could not be disproved.     

尿邻甲酚作为接触甲苯生物监测指标的探讨

目的探讨尿邻甲酚作为接触甲苯生物监测指标的可能性。方法建立柱前衍生高效液相色谱法测定人体尿中邻甲酚,且使用该方法测定非职业及职业接触甲苯人群尿中邻甲酚水平,并进行接触评定。结果甲苯接触者尿邻甲酚水平为(2.61±1.94)mg/L,明显高于对照组[(0.32±0.23)mg/L],差异有显著性(P<0.001),且接触甲苯工人班后尿邻甲酚水平比班前明显升高,最高可达29倍。接触甲苯者尿邻甲酚水平与个体接触甲苯浓度明显相关(r=0.6295,P<0.01)。结论尿邻甲酚可以作为接触甲苯的生物监测指标。     

Investigation of toxicity through human cases and animal experiments--study of bromopropanes

In 1995, workers in a Korean electronic factory exhibited oligospermia or amenorrhea. We investigated the toxicity of 2-bromopropane used as an alternative to chlorofluorocarbons in the factory in animal experiments, and clarified that exposure to 2-bromopropane depletes spermatogenic cells in male rats and oocytes in female rats. Subsequently, we investigated the neurotoxicity of 2-bromopropane on the basis of the reported neuropathy in the Korean workers exposed to 2-bromopropane. For comparison, we employed 1-bromopropane, which is now used as a new alternative to chlorofluorocarbons. The results showed that 1-bromopropane is more neurotoxic than 2-bromopropane, causing harm to reproductive organs by inhibiting spermiation in the testis and impairing follicular development in the ovary. Shortly after the initial investigation of 1-bromopropane in animals, human cases were reported in the United States. Neurologic abnormalities in Chinese workers exposed to 1-bromopropane were also reported, such as the elongation of distal latency and lowered sense of vibration in the lower limbs. Thus, these serial studies revealed that 1-bromopropane is neurotoxic, but its dose-response relationship in humans remains unknown. In the investigation of 2-bromopropane toxicity, initial animal studies were designed on the basis of human studies, while in research on 1-bromopropane, animal studies preceded human studies and contributed to the prediction of toxicity in humans. However, the use of animal model is limited in its ability to predict the toxicity of chemicals introduced depending on species differences. Further studies should focus more on the differences and commonality between animals and humans in response to toxic agents.     

Neuro-reproductive toxicities of 1-bromopropane and 2-bromopropane

2-Bromopropane was used as an alternative to chlorofluorocarbons in a Korean electronics factory and caused reproductive and hematopoietic disorders in male and female workers. This causality was revealed by animal studies, and target cells were identified in subsequent studies. After identification of 2-bromopropane toxicity, 1-bromopropane was introduced to the workplace as a new alternative to ozone-depleting solvents. 1-Bromopropane was considered less mutagenic than 2-bromopropane, but, in contrast, animal experiments revealed that 1-bromopropane is a potent neurotoxic compound compared with 2-bromopropane. It was also revealed that 1-bromopropane has reproductive toxicity, but the target cells are different from those of 2-bromopropane. Exposure to 1-bromopropane inhibits spermiation in male rats and disrupts the development of follicles in female rats, in contrast to 2-bromopropane, which targets spermatogonia and oocytes in primordial follicles. After the first animal study describing the neurotoxicity of 1-bromopropane, human cases were reported. Those cases showed decreased sensation of vibration and perception, paresthesia in the lower extremities, decreased sensation in the ventral aspects of the thighs and gluteal regions, stumbling and headache, as well as mucosal irritation, as the initial symptoms. The dose–response of bromopropanes in humans and mechanism(s) underlying the differences in the toxic effects of the two bromopropanes remain to be determined.     

Methanol in urine as a biological indicator of occupational exposure to methanol vapor

Summary The exposure-excretion relationship and possible health effects of exposure to methanol vapor were studied in 33 exposed workers during the second half of 2 working weeks. Urinary methanol concentrations were also determined in 91 nonexposed subjects. The geometric mean value for methanol in urine samples from the latter was < 2 mg/1 (95% upper limit of normal, < 5 mg/l) when log-normal distribution was assumed. Among the exposed workers, the methanol level in urine samples collected prior to the work shift exceeded the 95% upper limit of normal. The time-weighted average intensity of exposure to methanol vapor was measured using personal sampling devices (in which water severed as an absorbent) in 48 cases of methanol exposure (i.e., 2 of the 33 exposed workers failed to provide urine samples, whereas 17 subjects were examined twice). Methanol concentrations in urine were determined in samples collected at the end of the shift from the 48 exposed cases as well as from 30 nonexposed controls. There was a significant correlation between the exposure to methanol vapor at concentrations of up to 5,500 ppm and the levels of methanol measured in the shift-end urine samples. The calculation indicated that a mean level of 42 mg methanol/l urine (95% confidence range, 26–60 mg/kg) was excreted in the shift-end urine sample following 8 h exposure to methanol at 200 ppm (the current occupational exposure limit). Dimmed vision and nasal irritation were among the most frequent symptoms complained during work. Three cases showing clinical signs of borderline significance were identified.     

Respiratory findings in chemical workers exposed to low concentrations of organic and inorganic air pollutants

BACKGROUND: Occupational exposure to respiratory irritants may effect respiratory function in workers exposed to ambient air pollutants in the workplace. METHODS: We studied 567 male and 135 female workers employed in two chemical plants in Zagreb, Croatia. Measurements of the ambient concentrations of air pollutants were performed. The mean age of the men was 37 years and mean duration of employment was 12 years; a majority of these workers were smokers. The mean age of the women was 37 years with a mean duration of employment of 14 years; only one-third of the women smoked. An unexposed group of 340 male and 110 female unexposed workers was also studied. Acute and chronic work related symptoms were recorded for all workers. Ventilatory capacity was measured by recording maximum expiratory flow-volume (MEFV) curves. RESULTS: There were higher prevalences for all chronic respiratory symptoms in exposed than in unexposed workers particularly among women, a majority of which were nonsmokers. Occupational asthma was recorded in three (0. 5%) of the men and in two (1.5%) of the women workers. Logistic regression analysis indicated that the presence of chronic respiratory symptoms among exposed workers was primarily associated with the amount of smoking. Additionally, there were high prevalences of acute symptoms during the work shift. Among the chemical workers these were greatest for eye irritation (male: 43. 9%; female: 51.9%), dryness of the throat (male: 43.4%; female: 57. 0%) and irritation of the throat (male: 37.4%; female: 56.6%). Ventilatory capacity data among the chemical workers demonstrated that most of the measured tests, particularly the FVC and FEV1 were significantly decreased compared to predicted (P < 0.01 or P < 0. 05)). In particular nonsmoking women exhibited abnormal lung function. The effect of smoking among exposed workers was demonstrated on all ventilatory capacity tests by regression analysis for all measured respiratory parameters. Both length of exposure and age were correlated with lung function loss for FVC. Measured pollutant levels were for the most part within acceptable standard limits. CONCLUSIONS: Our data suggest that in this population of chemical workers exposed to low levels of pollutants respiratory symptoms were primarily associated with smoking. Environmental effects, possibly due to an interaction of pollutants were also suggested.     

1—溴丙烷工厂工人健康状况调查及接触生物标记物的研究

目的 分析1-溴丙烷毒性并评价其危险度，探讨适宜的接触生物标记物，方法 对37名工人进行问卷调查。血液学指标和血生化指标的测定。包括垂体激素和性激素测定。以该工厂工人为接触组，食品厂工人为对照组，比较两组间的血浆，脶酸激酶（CK）活性和血浆肌酸激酶M亚基（CK-M）。尿中1-溴丙烷用气相色谱仪检测，个体暴露蓄积水平用个体采样器估测。结果 接触组工人出现眼，鼻，口腔，喉的粘膜刺激症状。部分工人出现眩晕，可能是神经系统的反应。结论 接触1-溴丙烷引起的主诉症状提示它能刺激上呼吸道粘膜，在约100mg/m^3浓度水平可影响中枢神经系统，尿1-溴丙烷浓度有望成为接触的生物标记物。     

Homovanillic acid (HVA) and manganese in urine of workers exposed in a ferromanganese alloy plant

Forty workers occupationally exposed to manganese in a ferromanganese alloy plant and twenty-five controls were investigated in order to assess the validity of urinary homovanillic acid (HVA) as a potential indicator of early effects of manganese intoxication. None of the exposed workers showed signs and symptoms of typical manganese intoxication, but most of them reported subjective symptoms which may be related to a prodromic phase of manganism. Urinary HVA levels were not significantly different among the groups under study. On the other hand, mean urinary manganese levels were higher in the exposed group (compared with the controls). A negative correlation between urinary HVA and duration of exposure to manganese was found.     

Monitoring risks in association with exposure levels among wastewater treatment plant workers

OBJECTIVE: To investigate the relationship between exposure to hydrogen sulfide and endotoxin during specific job tasks and health symptoms among wastewater treatment plant (WWTP) workers. METHODS: The exposure levels for specific tasks were measured by personal monitoring. The health symptoms of WWTP workers were compared with those of water treatment plant workers through a questionnaire survey. RESULTS: Exposure levels for all monitored tasks were less than 1 ppm for hydrogen sulfide and 91 EU/m (endotoxin units/m) for endotoxin. Statistically higher odds ratios of respiratory, ocular and skin irritation, neurology, and gastrointestine symptoms were shown among WWTP workers compared with water treatment plant workers. Tasks related to sludge handling and plant inspection showed statistically significant associations with memory/concentration difficulties, throat irritation, and stomach pain. CONCLUSIONS: These results suggest that exposure control programs for specific job tasks and work locations are needed.     

Neurologic abnormalities in workers of a 1-bromopropane factory

We reported recently that 1-bromopropane (1-BP; n-propylbromide, CAS Registry no. 106-94-5), an alternative to ozone-depleting solvents, is neurotoxic and exhibits reproductive toxicity in rats. The four most recent case reports suggested possible neurotoxicity of 1-BP in workers. The aim of the present study was to establish the neurologic effects of 1-BP in workers and examine the relationship with exposure levels. We surveyed 27 female workers in a 1-BP production factory and compared 23 of them with 23 age-matched workers in a beer factory as controls. The workers were interviewed and examined by neurologic, electrophysiologic, hematologic, biochemical, neurobehavioral, and postural sway tests. 1-BP exposure levels were estimated with passive samplers. Tests with a tuning fork showed diminished vibration sensation of the foot in 15 workers exposed to 1-BP but in none of the controls. 1-BP factory workers showed significantly longer distal latency in the tibial nerve than did the controls but no significant changes in motor nerve conduction velocity. Workers also displayed lower values in sensory nerve conduction velocity in the sural nerve, backward recalled digits, Benton visual memory test scores, pursuit aiming test scores, and five items of the Profile of Mood States (POMS) test (tension, depression, anxiety, fatigue, and confusion) compared with controls matched for age and education. Workers hired after May 1999, who were exposed to 1-BP only (workers hired before 1999 could have also been exposed to 2-BP), showed similar changes in vibration sense, distal latency, Benton test scores, and depression and fatigue in the POMS test. Time-weighted average exposure levels in the workers were 0.34-49.19 ppm. Exposure to 1-BP could adversely affect peripheral nerves or/and the central nervous system.     

Symptoms and immunologic markers among vulcanization workers in rubber industries in southern Sweden

OBJECTIVES: The aim of this study was to estimate the risk of symptoms and the possible derangement of levels of immunologic markers for contemporary Swedish rubber workers. Furthermore, the relation between exposure and these biomarkers of response was examined using urinary levels of 2-thiothiazolidine-4-carboxylic acid (TTCA), which reflect the exposure. METHODS: Included in the study were 166 exposed workers and 117 controls. Medical and occupational histories were obtained in structured interviews. Symptoms were recorded, and immunologic markers were analyzed in blood. Urinary levels of TTCA were determined by liquid chromatography tandem mass spectrometry. RESULTS: Compared with the controls, the exposed workers had increased risks of eye symptoms [odds ratio (OR) 3.0], nose bleeds (OR 4.0), burning and dry throat (OR 3.0), hoarseness (OR 2.4), severe dry cough (OR 3.8), nausea (OR 4.3), and headache (OR 2.5). When the exposed workers were divided into three groups according to the TTCA levels, the highest risks were observed among the exposed workers with intermediate TTCA levels. Furthermore, the exposed workers in all of the TTCA subgroups had elevated concentrations of total immunoglobulin G when compared with the controls. Elevated concentrations of leukocytes, neutrophils, and eosinophils were observed in the group with high TTCA levels. CONCLUSIONS: This work shows an increased risk of several symptoms and elevated levels of some immunologic markers among exposed workers in Swedish rubber industries. In addition, relationships between urinary levels of TTCA and some biomarkers of response were reported.     

Urinary 1-hydroxypyrene concentrations in Chinese coke oven workers relative to job category, respirator usage, and cigarette smoking

BACKGROUND: 1-Hydroxypyrene (1-OHP) is a biomarker of recent exposure to polycyclic aromatic hydrocarbons (PAHs). We investigated whether urinary 1-OHP concentrations in Chinese coke oven workers (COWs) are modulated by job category, respirator usage, and cigarette smoking. METHODS: The present cross-sectional study measured urinary 1-OHP concentrations in 197 COWs from Coking plant I and 250 COWs from Coking plant II, as well as 220 unexposed referents from Control plant I and 56 referents from Control plant II. RESULTS: Urinary 1-OHP concentrations (geometric mean, micromol/mol creatinine) were 5.18 and 4.21 in workers from Coking plants I and II, respectively. The highest 1-OHP levels in urine were found among topside workers including lidmen, tar chasers, and whistlers. Benchmen had higher 1-OHP levels than other workers at the sideoven. Above 75% of the COWs exceeded the recommended occupational exposure limit of 2.3 micromol/mol creatinine. Respirator usage and increased body mass index (BMI) slightly reduced 1-OHP levels in COWs (P < 0.1). Cigarette smoking significantly increased urinary 1-OHP levels in unexposed referents (P < 0.005), but had no effect in COWs (P > 0.1). CONCLUSIONS: Chinese COWs, especially topside workers and benchmen, are exposed to high levels of PAHs. Urinary 1-OHP concentrations appear to be modulated by respirator usage and BMI in COWs, as well as by smoking in unexposed referents.     

接触对甲苯磺酸作业人员健康状况调查

目的了解3家企业接触对甲苯磺酸作业人员的健康状况,为保护职业接触者身体健康提供依据。方法采用自制的健康状况调查表对生产和使用对甲苯磺酸的3家企业194名作业人员（接触组）进行调查,并分别选取3家企业不接触对苯磺酸的166人的对照组,结合职业健康检查情况,综合分析其健康状况。结果接触对甲苯磺酸作业人员的急性刺激症状发生率（甲企业49．7％、乙丙企业51．0％）高于对照组（甲企业12．9％、乙丙企业23．8％）,差异有统计学意义（P〈0．01）;其职业健康检查异常情况构成与对照组的差异无统计学意义（P〉0．05）。结论接触对甲苯磺酸的作业人员健康损害主要表现为眼睛刺激、咳嗽、皮肤刺激等急性刺激症状,建议应加强工作场所通风及个人防护,尤其是皮肤防护。     

1-溴丙烷对接触工人神经毒性的剂量-效应关系

目的 探索1-溴丙烷(1-BP)对接触工人神经毒性的剂量-效应关系.方法 对国内1-BP生产工厂进行职业卫生现场调查.按1:1比例选取年龄配对的接触组和对照组女工各71人.作业环境中1-BP的浓度用直读式检气管测定,工人的8 h时间加权平均(TWA)浓度用个体采样器测定.对工人进行问卷调查、神经内科检查、神经传导速度检查、振动觉检查、血常规和血液生化检查.根据TWA值和TWA×工龄值将接触工人分为3个剂量组,进行剂量-效应关系分析.使用USEPA BMDS 2.1软件计算1-BP毒作用基准剂量(BMD)和基准剂量下限值(BMDL).结果 TWA-8 h浓度范围为0.35～535.19 mg/m3,(均值14.08 mg/m3).剂量-效应关系分析表明,1-BP接触工人在运动神经远端潜伏期(DL,线性回归系数为0.0666)、双足振动觉(线性回归系数分别为0.157 2和0.193 9)、肌酸激酶水平(线性回归系数为-1.0464)和促甲状腺激素水平(线性回归系数为0.102 4)等指标与1-BP有剂量依赖关系(P<0.05).依据DL资料计算TWA-8 h的BMD值和BMDL值分别为55.55和30.78 mg/m3.结论 1-BP对接触工人具有神经毒性,可引起胫神经DL延长、振动觉下降的剂量依赖性改变.     

Morbidity among municipal waste incinerator workers: a cross-sectional study

OBJECTIVES: In order that the occupational exposures and health risks for municipal waste incinerator operators be better determined, a study was carried out in three centres. METHODS: A transversal study was carried out for 102 male incinerator workers matched for age with 94 male workers from other industrial activities. Three groups of exposed workers were considered (group 1: "crane operators" and "equipment operators"; group 2: "furnace " workers; group 3: "maintenance" and "effluent-treatment" workers). Data were collected through a questionnaire and medical examination. The respiratory function was explored and blood samples were taken for biological analysis. Statistical analysis using chi(2) or Student's test, and calculation of odds-ratio (OR) using logistic regression analysis were performed. RESULTS: There were no significant differences in general symptoms between the two groups. Skin symptoms (OR =4.85; 2.04-11.51 for the "maintenance and effluent" workers) were more often observed in the exposed group. An excess of respiratory problems was also encountered: daily coughing ["maintenance and effluent" groups (OR =2.55; 0.84-7.75); "furnace men" (OR =6.58; 2.18-19.85)]. A significant relationship between exposure and the decrease of several pulmonary parameters was observed. The liver and haematological tests were well within the normal range; nevertheless, a slight but significant increase in the white blood cells was observed in the exposed group. Higher blood lead levels were found for exposed workers. CONCLUSION: There were few adverse health effects in our morbidity study but skin irritation and cough were more frequent in the exposed workers. A slight decrease in pulmonary function was observed. These findings are in agreement with those of several other studies.     

Perceived odor and irritation of isopropanol: a comparison between naïve controls and occupationally exposed workers

OBJECTIVES: To assess sensory irritation levels from isopropanol (IPA) unconfounded by subjective evaluations of odor for comparison against the recommended exposure limits (400 ppm threshold limit value (TLV); American Conference of Governmental Industrial Hygienists). METHOD: The lateralization method was used to assess intra-nasal irritation thresholds for IPA, while odor detection thresholds were also measured. Thresholds for 1-butanol and phenyl ethyl alcohol (PEA) were obtained as positive and negative irritant controls. To compare potency and hedonic characteristics, subjects provided subjective ratings of odor, irritation and annoyance intensity for three concentrations of each chemical. Workers occupationally exposed to IPA ( n=26) were compared with previously unexposed controls ( n=26). RESULTS: The (geometric) mean odor detection threshold for IPA was slightly higher among exposed workers than controls (39 ppm vs. 11 ppm). Lateralization thresholds measuring intra-nasal irritation were elevated when compared with controls (6,083 ppm in exposed workers vs. 3,361 ppm in na?ve controls), with a significantly higher proportion of phlebotomists being unable to lateralize the maximum concentration regarded as safe, than controls. Calculations of the 6th percentile for lateralization thresholds revealed that 95% of the sample did not experience sensory irritation below 512 ppm. Thus, while odor detection thresholds were well below the current recommended exposure limits, the irritation thresholds were well above these values. The odor, irritation and annoyance from IPA was perceived, on average, as between weak and almost strong, from lowest to highest concentration. CONCLUSIONS: The results indicate that current exposure guidelines would be adequately protective of the acute adverse effect of nasal sensory irritation, as operationally defined by the intra-nasal lateralization threshold. Exposures to higher concentrations should perhaps be evaluated on the basis of existing knowledge about systemic, rather than local (e.g., irritation), toxic effects. IPA appears to be a weak sensory irritant and occupational exposure to IPA appears to elicit small changes in sensitivity that do not generalize to other odorants (e.g., PEA and 1-butanol) and are likely to be reversible.