Characterization of influenza outbreaks in Lebanon during the 2013/14 and 2014/15 seasons.

Despite the significant burden of influenza outbreaks, active disease monitoring has been largely absent in the Middle East, including Lebanon. In this study we characterized influenza virus in 440 nasopharyngeal swabs collected from patients with acute respiratory infections during two influenza seasons in Lebanon. Influenza A(H3N2) was dominant in the 2013/14 season while the A(H1N1)pdm09 and B/Yamagata strains were most prevalent in the 2014/15 season. All tested isolates were susceptible to 4 neuraminidase inhibitors (oseltamivir, zanamivir, peramivir and laninamivir). Genetic analysis of the haemagglutinin gene revealed multiple introductions of influenza viruses into Lebanon from different geographic sources during each season. Additionally, large data gaps were identified in the Middle East region, as indicated by the lack of current influenza sequences in the database from many countries in the region.

Deficiency in WT1-targeting microRNA-125a leads to myeloid malignancies and urogenital abnormalities.

The Wilms' tumor gene WT1 is overexpressed in leukemia and solid tumors and has an oncogenic role in leukemogenesis and tumorigenesis. However, precise regulatory mechanisms of WT1 overexpression remain undetermined. In the present study, microRNA-125a (miR-125a) was identified as a miRNA that suppressed WT1 expression via binding to the WT1-3'UTR. MiR-125a knockout mice overexpressed WT1, developed myeloproliferative disorder (MPD) characterized by expansion of myeloid cells in bone marrow (BM), spleen and peripheral blood, and displayed urogenital abnormalities. Silencing of WT1 expression in hematopoietic stem/progenitor cells of miR-125a knockout MPD mice by short-hairpin RNA inhibited myeloid colony formation in vitro. Furthermore, the incidence and severity of MPD were lower in miR-125a (-/-) mice than in miR-125a (+/-) mice, indicating the operation of compensatory mechanisms for the complete loss of miR-125a. To elucidate the compensatory mechanisms, miRNA array was performed. MiR-486 was occasionally induced in compete loss of miR-125a and inhibited WT1 expression instead of miR-125a, resulting in the cancellation of MPD occurrence. These results showed for the first time the post-transcriptional regulatory mechanisms of WT1 by both miR-125a and miR-486 and should contribute to the elucidation of mechanisms of normal hematopoiesis and kidney development.

Alcoholism and affective disorder: clinical course of depressive symptoms.

OBJECTIVE: This study compared the severity of and the change in depressive symptoms among men with alcohol dependence, affective disorder, or both disorders during 4 weeks of inpatient treatment. METHOD: After their primary and secondary psychiatric disorders were defined with the use of criteria based on chronology of symptoms, 54 unmedicated men entering treatment for alcohol dependence or affective disorder were assessed for 4 consecutive weeks with the Hamilton Depression Rating Scale. RESULTS: The findings indicate that the rate of remission of depressive symptoms was consistent with the primary diagnosis. Depressive symptoms remitted more rapidly among the men with primary alcoholism than among those with primary affective disorder. However, a minimum of 3 weeks of abstinence from alcohol appeared to be necessary to consistently differentiate the groups with dual diagnoses on the basis of their current depressive symptoms. Alcohol dependence occurring in conjunction with primary affective disorder did not intensify presenting depressive symptoms or retard the resolution of such symptoms. CONCLUSIONS: Diagnoses of alcohol dependence and affective disorder based on symptom chronology appear to have prognostic significance with respect to remission of depressive symptoms in men with both diagnoses. Depressive symptoms of dysphoric mood, dysfunctional cognitions, vegetative symptoms, and anxiety/agitation showed different rates and levels of remission across the primary diagnostic groups.

Auditory threshold reduction on alcohol ingestion.

RATIONALE: Auditory threshold (AT) measurement method has become the standard behavioral procedure for describing auditory sensitivity. Therefore, the AT measurement method is applicable to evaluation of auditory function. However, only a few studies have been performed to clarify the alteration of audibility under the influence of alcohol on normal humans by measurement of AT. OBJECTIVE: The fact that blood alcohol concentration (BAC) is influenced by the dose of alcohol and the time of measurement suggests that the effects of alcohol may also be altered by the same factors. The present study was conducted to elucidate how alcohol ingestion method affects the AT at a wider range from lower to higher frequency in the time course. METHODS: Fifteen paid Japanese (seven men and eight women, 20-33 years of age) were employed in AT measurements at an octave frequency ranging from 250 to 8,000 Hz before and 5, 30, 60, 120, 240 and 480 min after drinking various amounts (125, 250, 500 and 1,500 ml) of normal beer (5% alcohol) or alcohol-free beer. RESULTS: The AT was significantly reduced within 30 min after the ingestion of 250 and 500 ml of beer, occurring on and after peak BAC. The reducing effect disappeared 480 min after ingestion. CONCLUSIONS: Drinking extra small amounts of alcohol induces the reduction of AT. The effect of alcohol on AT is altered by the alcoholic dose used in testing.

Effects of different durations of exercise on macrophage functions in mice.

The effects of differing durations of daily exercise on macrophage functions in mice were studied. Male ICR mice aged 4 wk were divided into five groups: a nonexercise group (control) and four exercise groups with differing daily exercise durations of 15--120 min (Exr groups). The exercise applied was 5 days/wk treadmill running at 13 m/min for 12 wk. The potentiation of the phagocytosis function of the reticuloendothelial system and the glucose consumption of peritoneal macrophages in the Exr 30, 60, and 120 groups were significantly higher than those in the control group. Superoxide anion production of peritoneal macrophages in both the absence and the presence of phorbol 12-myristate 13-acetate in the Exr 60 and 120 groups was significantly higher than that in the control group. The acid phosphatase and beta-glucuronidase activities of peritoneal macrophages in the Exr 30, 60, and 120 groups were significantly increased. These results suggest that treadmill running exercise for at least 30 min/day (30--120 min) effectively enhances macrophage functions in mice. These data provide preliminary evidence indicating that chronic exercise-induced increases in phagocytic activity exhibit a dose-dependent relationship with exercise duration.

Effects of low- and high-frequency local vibration on the occurrence of intimal thickening of the peripheral arteries of rats.

Rats were exposed to local vibration in a study of the differences in the effects between low and high frequencies of vibration on the vessel wall of peripheral arteries. The vibration was delivered at frequencies of 30 and 480 Hz under a constant acceleration of 5g. The duration of the vibration exposure was 30 d. The changes in the arteries were studied pathohistologically and hematologically. Three of the five rats exposed to 30 Hz and three of the five rats exposed to 480 Hz showed disruption of the internal elastic lamina. The disruption was followed by focal cell proliferation with regenerative formation of collagen and elastic fibers. The vascular changes observed after vibration exposure could not be explained by changes in plasma lipid concentrations. These results suggest that not only low frequencies of vibration, but also high frequencies have harmful effects on the intima of small arteries.

Subjective symptoms among motorcycling traffic policemen.

OBJECTIVES: This study investigated the prevalence of subjective symptoms among current and former motorcycling policemen. METHODS: The subjects of this study consisted of 46 current and 72 former motorcycling traffic policemen from a certain city located in the central part of Japan. They were requested to reply to questions on a self-administered questionnaire regarding age, work history, and subjective symptoms (16 items) during the month preceding the completion of the questionnaire. RESULTS: Shoulder stiffness and low-back pain were frequently encountered. On the whole, the prevalence of subjective symptoms was higher among the current motorcycling policemen, even though they were younger. Assessing the prevalence of subjective symptoms by the median value of experience of motorcycle riding revealed that the high-exposure subgroup in the group that currently ride motorcycles had higher prevalence rates for all the symptoms. CONCLUSIONS: The prevalence of subjective symptoms among currently motorcycling traffic policemen seems to be transient, and it declines after the cessation of motorcycle riding or the reallocation to other worktasks, such as office work.

Usefulness of blood parameters, especially viscosity, for the diagnosis and elucidation of pathogenic mechanisms of the hand-arm vibration syndrome.

In the present study it was found that, in vibrating-tool operators with Raynaud's phenomenon, whole blood viscosity was significantly higher than in operators without Raynaud's phenomenon at shear rates from 230 to 11.5 s-1. In addition rats were experimentally exposed to local vibration (60 Hz, 5 g) on their hind limbs for 4 h/d for 30 or 90 d. In the case of 30-d exposure, the small arteries in the exposed site did not change. However, after exposure for 90 d, disruption of the internal elastic lamina was observed in the small arteries. The disruption was followed by focal cell proliferation with regenerative formation of collagen and elastic fibers. The fibro-cellular thickening of the intima was further augmented, and, in addition, a complete stenosis of the small lumen of the small artery was observed. Medial thickness did not show significant differences between the control and exposed groups for either exposure duration. The whole blood viscosity was significantly increased by the 90-d but not by the 30-d exposure. These results suggest that there are some relationships between the increase in whole blood viscosity and the intimal thickening of some small arteries in the exposed site.

Operating hand-held vibrating tools and prevalence of white fingers.

Hand-transmitted vibration levels (HTVLs) and the prevalence of vibration-induced white finger (VWF) and numbness of the hands were investigated in eight groups of subjects operating various hand-held vibrating tools. The prevalence rates of Raynaud's phenomenon (RP) and numbness of the hands in 1,027 males and 1,301 females not occupationally exposed to vibration were compared to those of the exposed subjects. The prevalence of VWF was in the range of 0.0-4.8% in subjects exposed to HTLVs of between 1.1 to 2.5 m/s2 and reached 9.6% in a group of workers exposed to HTLVs of 2.7-5.1 m/s2. The latter group showed a significant difference (P < 0.05) in the prevalence of VWF compared to the 2.7% prevalence of RP in male subjects of the general population. The prevalence of VWF in female subjects exposed to vibration (4.3%) was not significant compared to the prevalence of RP in females of the general population (3.4%). The prevalence rates of numbness of the hands were between 6.5% and 30.4% in the exposed groups and in the range of 13.4-29.5% in the general population. It was concluded that in decisions concerning quantitative recommendations for vibration exposure, the prevalence of VWF should be employed. To decrease the risk of developing VWF, estimated vibration safety values for 4 h and 2 h daily exposures are discussed.

Effect of hand-arm vibration on inner ear and cardiac functions in man.

To evaluate distant effects of hand-arm vibration we studied Finnish forestry workers using chain saw during the years 1972 through 1990. The hearing was tested annually and individual regression curves for sensorineural hearing loss (SHL) were calculated. Robinson's model was used in prediction of SHL. The heart rate variation (HRV) indexes at rest and during deep breathing test were analyzed to measure autonomic nervous function. In Robinson's model the measured SHL (17.8 dB) respected the predicted SHL (17.2 dB). The subjects with VWF had on average, 10 dB greater hearing loss than those who did not have VWF. The regression model based increase of hearing loss during follow up correlated with ageing, not to VWF. The intercept differed significantly in those with VWF from those without VWF. We found a significant difference between HRV indexes during deep breathing test in those with the shortest and those with the longest vibration exposure. The HRV decreased with age, but multiple regression analysis showed that the total exposure time to vibration had an independent negative association with HRV indexes. Our results suggest that prolonged exposure to vibration caused by chain saw has negative effects an autonomic functions. The aggravated hearing loss in subjects with VWF may be due to vibration induced changes in the autonomic nervous system or internal factors of the blood vessels.

Increase of the cellular growth of old human diploid fibroblasts by radical scavenger: methanolic extract of broad beans.

The methanolic extract from broad beans (MEBB), which is comprised of phenolic compounds, has free-radical scavenging activity. The effects of MEBB on cytosolic antioxidant enzymes and cell proliferation were examined in cultures of old (78-84% life-span completed) WI-38 human diploid fibroblasts. Because catechin is polyphenol and has radical scavenging activity, it was used as the control in experiments. We observed that MEBB increased cellular growth when added to the cell culture. In MEBB at 40 and 120 micrograms/mL, the cell proliferation increased by 14 and 27%, respectively, as compared to the control. In catechin, cell proliferation increased as well. Regarding cytosolic glutathione peroxidase (GSH-Px) activity, treatment of old cells with MEBB at 40 and 120 micrograms/mL resulted in decreases as compared to the control. In contrast, catechin showed no similarities to the modification of GSH-Px activity. Cytosolic SOD activity was increased by treatment with 40 micrograms/mL MEBB, and the activity showed a gradual decrease with increased MEBB concentrations. A similar trend occurred in the cells treated with catechin (4-20 microM). These results suggest that cytosolic antioxidant enzyme activities in old cells may be modulated by MEBB treatment. We conclude that there may be a relation between the optimum MEBB concentration for the increase of cellular growth and the MEBB concentration required to exhibit a decrease in GSH-Px activity.

A study on the vibration-dose limit for Japanese workers exposed to hand-arm vibration.

To obtain a vibration-dose limit for Japanese workers exposed to hand-arm vibration, the prevalences of vibration-induced white finger (VWF) and numbness of the hand were studied in 5 different groups of workers exposed to segmental vibration. In addition, the prevalence of primary Raynaud's phenomenon (PRP) in the general population without occupational vibration exposure was computed. The vibration levels in the exposed groups (except chain saw operators) ranged from 124.1-129.2 dB (reference value, 10(-6) m/s2). The prevalence of VWF in these groups was 2.2-4.8%. This value was not statistically significant (p greater than 0.05) when compared to the prevalence of PRP in the general Japanese population (2.7-2.9% in our study and 0.5-4.6% in other surveys in Japan). Although the prevalence of numbness of the hands fluctuated among the groups, no significant differences could be demonstrated. Our results were then compared to those of previous reports by literature study [319 papers on hand-arm vibration syndrome (HAVS) and 25 reports on PRP]. At a glance the Japanese population showed a lower prevalence for PRP compared to other countries, which suggested that exposure to cold and biological abilities should also be considered to assess vibration syndrome. A comparison of the vibration characteristics of different tools and the occurrence of VWF in the hands of workers in the literature with those of our data suggested that a daily hand-arm vibration exposure at a level lower than 2.5 m/s2 (128 dB, reference value 10(-6) m/s2) could possibly decrease the risk of VWF among workers exposed to segmental vibration.

Low back pain among different groups of subjects exposed to hand-arm transmitted vibration.

OBJECTIVES: The purpose of this study was to investigate the prevalence of low back pain (LBP) among various groups of subjects exposed to hand-arm transmitted vibration, and to compare the prevalence of LBP of these subjects with that of non-exposed groups. METHODS: The subjects of this study were 13 groups of males and 3 groups of females of working population leaving in a certain city located in the central part of Japan. By means of a questionnaire, interviews, field visits, or annual health examination, information on age, working career, working posture, various types of tools used, and experience of having LBP during the 12 months preceding the completion of the questionnaire were collected. The subjects' age ranged between 22 and 69 years. All subjects were classified into 5 categories, and the prevalence of LBP was obtained for them. RESULTS: On the whole, complaints of LBP among male and female green tea and strawberry farmers were most frequent. There was a large variation (16.0-72.2%) in the prevalence of LBP among subjects operating vibrating tools. Among three groups of health care professionals, the prevalence of LBP was in the range of 36.5-53.0%. The senior doctors had less complaints of LBP. The prevalence of LBP among subjects who had sedentary jobs was in the range of 41.7-45.9%, and almost as high as that in blue-collar workers using vibrating tools. The prevalence of LBP among females exposed to hand-arm transmitted vibration was between 26.1 and 63%. The prevalence rates of LBP among vibration exposed subjects were plotted against the vibration magnitude of tools used by the same subjects reported in our previous study; however, no significant correlation could be obtained between the prevalence of LBP and vibration values. CONCLUSIONS: Exposure to segmental vibration is less likely to be a risk factor in increasing prevalence of LBP. A higher prevalence of LBP in some groups provide strong evidence for a dominant work-related etiology in developing LBP. Regarding data presented in this study and by a review on scientific literature, suggestions for improving working posture were presented. It seemed that to decrease the risk of LBP among these subjects, special attention should be paid to stimulating the adoption of an ergonomic working posture and to ergonomic training.

Some aspects of occupational safety and health in green tea workers.

The objectives of this study were to evaluate the health and safety conditions of 36 male and 27 female green tea workers who were aged 40-69 years and had worked for at least 5 years in green tea production procedures. The Mean +/- SD of age was 57.1 +/- 5.8 years in males and 54.4 +/- 6.4 years in females. The mean working career was 26.1 +/- 9.5 years and 24.3 +/- 9.1 years, respectively. The most commonly subjective complaints developed while at work was pain in the lower back at a rate of 72.2% in males and 63.0% in females. Regarding persistent subjective complaints, female workers had significantly (P < 0.05) higher prevalence rate for breath shortness (25.9%) compared to that of male workers (5.6%). It was observed that the male workers whose occupational career was equal to or more than 28 years had significantly higher prevalence rates for stiffness in the neck and pain in the arms, compared to those of male workers whose occupational career was less than 28 years. The prevalence of nasal allergy was 11.1% either in the male or female workers. The total rate of accidents during working hours in the male workers was 22.2%, and that in the female subjects was 18.5%. The mean frequency weighted vibration magnitude produced by using tea-leaf plucker was in the range of 2.4-3.5 m/s2. The mean equivalent A-weighted noise level while using the same equipment was 100.6 +/- 5.0 dB(A). The need for occupational safety and health programs in these small farm settings are discussed.

Exposure to segmental vibration and noise in orthopaedists.

The results of several field visits to orthopaedic clinics and the data obtained from a postal questionnaire were used to evaluate the segmental vibration and noise exposure levels in orthopaedists. The analysis of 54 (85.7%) complete questionnaires showed that hand-held plaster saws were used (Mean +/- SE, 12.3 +/- 1.7 min/week) more often than other tools. The mean frequency-weighted acceleration levels while using these tools were in the range of 2.3-2.4 m/s2. The A-weighted sound pressure levels in orthopaedic clinics while using the same instruments were in the range of 88.7-93.4 dB(A). Regarding the vibration magnitude and exposure time, segmental vibration seems not to be a serious problem in orthopaedists. However, the noise level produced from operating orthopaedic tools may have deleterious effects such as masking of speech communication among staff members. Patients' sleep or rest was thought to be disturbed by such noise levels.

Noise exposure level while operating electronic arcade games as a leisure time activity.

In order to study noise levels associated with electronic arcade games, noise measurements were made in 3 selected game centers and 192 samples were taken in each location. The background noise was recorded at a level of 61 dB(A) and 64 dB(C). When the electronic games were performed these levels of noise reached to 88 approximately 90 dB(A). The 1/3 octave bands analyzing sound pressure levels showed that more intense noise levels arose in a frequency range between 0.5 and 2.0 kHz. The computed values for noise pollution levels (LNP) and L90 (fast response A-weighted sound level exceeded 90% of the measurement time) ranged from 93.3 to 96.6 and from 85.1 to 87.3 dB(A), respectively. Concerning our results and according to Melnic (1979), it was estimated that these levels of noise might cause 4-8 dB temporary threshold shift (TTS) at 4.0 kHz in an individual with less than one hour of exposure to such a level of noise. As for the employees of the 3 game centers, the 8-hr equivalent continuous sound levels (Leq,8) were in the range of 80.3 approximately 87.5 dB(A), although their exposure time could not be exactly determined. It was suggested that: 1) The maximum levels should be limited to a reasonable level, either by the manufacturers or by the game center owners; 2) Education programs in industry should inform the employees about other factors outside the work that may affect their hearing; and 3) For policy-making on hearing conservation, recreational warning and standards should be established.

Noise in aerobic facilities.

Noise levels were evaluated before and during aerobic sessions in 3 aerobic studios. In addition, hearing threshold levels (HTLs) of 10 female aerobic instructors with the mean (+/- SD) ages of 25.4 (+/- 2.4) years were measured before and 2 min after an aerobic session. The mean (+/- SD) of total instruction time of these subjects was 1274.0 (+/- 704.9) h. Before the aerobic session, noise level was 63 dB(A) and increased to 87 dB(A) during a warm-up period. The highest noise levels of 93-96 dB(A) were recorded during a peak exercise period and decreased to 73 dB(A) during a cool-down period. The dominant spectra of sound pressure levels (SPLs) during the aerobic session were in the frequency range of 1-2 kHz at levels of 75-88 dB(C). The mean values of HTL obtained for each ear of these subjects were between 5 and 15 dB in the frequency range of 1-8 kHz. No significant differences in the mean HTLs of pre- and post-aerobic sessions could be obtained. The mean values of HTL of two groups of subjects divided by their total instruction time (n = 5 in each group, and p < 0.01 in their total instruction time) were quite comparable.

Finger skin temperature and laser-Doppler finger blood flow in subjects exposed to hand-arm vibration.

OBJECTIVES: This study was aimed to assess the peripheral circulatory functions of forestry workers exposed to hand-arm vibration, using simultaneous measurements of finger skin temperature (FST) and finger blood flow (FBF). METHODS: The subjects were five men with vibration-induced white finger (VWF), four subjects with numbness in their hands and five exposed controls without any signs or symptoms related to vibration syndrome. Simultaneous measurements of FST and laser-Doppler FBF were performed before, during and following a 10-min recovery period after the hand was immersed in cold water (10 degrees C, 10 min). Partitional measurements of finger blood flows could be made between the capillaries and deeply located vessels using two laser-Doppler flow probes having narrower and wider optic fiber separations. RESULTS: The FST as well as the FBF of the capillary and deeply located vessels during and following the cold immersion test in those with VWF and in the subjects with numbness had a slight increase immediately following the cold immersion and no tendency to be augmented as the time span increased. After the cold immersion test, the control group had significantly greater FST and FBF compared to other groups. Particularly, from the 5th to the 10th min after the cold provocation, the values of FBF of the deeply located vessels in those with VWF were significantly lower than the controls. During the course of observation, the FST had significantly linear relationship with the recorded capillary and deep FBF values, and that was much closely correlated with the deep FBF (i.e., P < 0.01 in each selected condition). The slope of the regression lines in the capillary were steeper and shallow in the deep FBF. CONCLUSIONS: In addition to the measurement of capillary FBF, more detailed and accurate information on the peripheral circulatory functions of vibration-exposed subjects can be obtained by including the assessment of the deep FBF.

A four-year follow-up study on subjective symptoms and functional capacities in workers using hand-held grinders.

Fifty-three grinders in the metal industry were re-examined 4 years after their first examination. Information about age, occupation, daily vibration exposure, drinking and smoking habits, and presence of subjective symptoms such as vibration-induced white finger (VWF), and numbness and pain in the fingers was collected during the first and second examination. Cold provocation test (10 degrees C/10 min) was also employed to evaluate disturbances in the peripheral circulatory and peripheral nerves in all subjects. The frequency-weighted vibration acceleration of various types of hand-held tools was measured. There was no subject with VWF at the first examination; however, during the course of follow-up, two cases (3.8%) of VWF with latent interval of more than 25 years were diagnosed. Prevalence of numbness in the fingers and shoulder stiffness was significantly higher at the second examination. When the prevalence of subjective symptoms was tested by the subjects' total operating time (TOT) during the 4-year follow-up period, those whose TOT was equal to or more than 2500 hours showed higher prevalence compared to the other subgroup. The paired values of recovery rate of finger skin temperature and vibration sensation threshold after the cold water immersion test were significantly different at the first and second examination. On average, the diminution of hand-grip force during the 4-year follow-up course was 7.4%; the difference being significant at 0.01 level. Significant differences in the paired data of pinching power and tapping ability could be detected. The frequency-weighted vibration acceleration of various tools was in the range of 1.1-4.6 m/s2. It was concluded that: (1) prolonged occupational exposure to the vibration of hand-held grinding tools should be considered as a risk factor causing disturbances in the hand-arm system of the operators; (2) the results of recovery rate of finger skin temperature and the vibration sensation threshold seemed to be appropriate indicators for the assessment of peripheral vascular and peripheral nerve disturbances in workers exposed to hand-arm vibration; and (3) to reduce the subjects' physical stress, attention should be paid to ergonomic factors.

A survey on noise exposure level in an aluminum can production plant.

The present investigation was designed to quantify noise exposure of laborers at various sections of an aluminum can production plant. The acoustic environment in each area was described by sound pressure level (SPL). Decibel (dB) readings were taken for a range of individual frequencies and weighting scales (A and C). Speech interference level (SIL) values for laborers in different production sections were also determined. Moreover, by means of a personal noise dosimetry technique, the equivalent continuous noise exposure level (dB(A)) during an 8-h shift (Leq, 8) was computed. The results obtained were as follows. Spectral analysis of the noise indicated that high SPL associated with high frequency noise exceeded the permissible limit against hearing damage, and it generally amounted to levels higher than 90 dB(A), whereas those inside the control rooms were in the range of 54-60.5 dB(A). Assessment of the results obtained from personal noise dosimeters also revealed that the Leq,8 values were higher than the prescribed limit (85 dB(A)). By preliminary audiometric examinations on the right ears of workers, hearing threshold shifts (HTS) were noticed in the range of 7-11 dB at 1 kHz and 12-16 dB at 4 kHz. With regards to the SIL values (93.2-96.5 dB(A)) which were more than the maximum vocal effort, communication between workers and/or with supervisor were appraised to be very difficult (shouting) or impossible. It was concluded that (a) the dB readings observed in this survey indicate a potentially serious possibility of hearing disability, even though high level of HTS could not be noticed in the preliminary audiometric test, and (b) the risk of accidents should also be taken into account regarding the nonauditory effects of such a high level of noise. We suggest that (1) minimizing the transmission of noise through acoustical countermeasures need to be considered, and (2) introducing a schedule comprising on-time and off-time could be beneficial in a workers' health conservation program.