Evaluation of the efficiency of respiratory protective equipment based on the biological monitoring of styrene in fibreglass reinforced plastics industries

Occupational exposure to VOCs and carbonyl compounds in beauty salons and health risks associated with it in South Korea

Long-term exposure to volatile organic compounds (VOCs) and carbonyl compounds in beauty products may adversely impact the health of beauty salon technicians. Previous studies have focused on assessing indoor air concentrations of chemicals, such as benzene and toluene, and not on personal exposure concentrations. This study measured the indoor and personal exposure concentrations of VOCs and carbonyl compounds in fifty-three beauty salons in Korea. Non-carcinogenic and carcinogenic risks and sensitivity were analyzed using the Monte Carlo simulation technique. The indoor and personal exposure concentrations of acetone were 82.24 µg/m³ and 104.97 µg/m³, respectively, the highest among all measured chemicals. Beauty salon technicians who experienced adverse health effects had significantly higher concentrations of acetone, benzaldehyde, and toluene than those who did not experience adverse health effects (p-value < 0.05). The average hazard quotients of formaldehyde and acetaldehyde were higher than the acceptable risk level (1), and the average cancer risks of formaldehyde exceeded the acceptable risk level (10^-6). Wearing personal protective equipment was the most efficient risk reduction strategy for reducing the non-cancer risks of acetaldehyde and formaldehyde and the carcinogenic risks of formaldehyde. The results of this study can be used as a basis for reducing exposure to VOCs and carbonyl compounds among salon technicians.

Effects of Personal Protective Equipment Use and Good Workplace Hygiene on Symptoms of Neurotoxicity in Solvent-Exposed Vehicle Spray Painters

Objectives

To assess the association between the use of personal protective equipment (PPE) and good workplace hygiene and symptoms of neurotoxicity in solvent-exposed vehicle spray painters.

Methods

Exposure control measures including PPE-use and workplace hygiene practices and symptoms of neurotoxicity were assessed in 267 vehicle repair spray painters. Symptoms were assessed using an adapted version of the EUROQUEST Questionnaire.

Results

Frequent respirator and glove use was inversely and significantly associated with symptoms of neurotoxicity in a dose-dependent manner (P < 0.05 for trend) with the strongest protective effect found for consistent glove use (odds ratios [OR] 0.1-0.2, P < 0.01, for reporting ≥10 and ≥5 symptoms). A clear dose-response trend was also observed when combining frequency of respirator and glove use (P < 0.05 for reporting ≥5 and ≥10 symptoms), with an overall reduction in risk of 90% (OR, 0.1, P < 0.01) for those who consistently used both types of PPE. Protective effects were most pronounced for the symptom domains of psychosomatic (P < 0.05 for trend, for combined PPE use), mood (P < 0.05), and memory and concentration symptoms combined (P < 0.05), with reductions in risk of >80%. Poor hygiene workplace practices, such as solvent exposure to multiple body parts (OR 3.4, P = 0.11 for reporting ≥10 symptoms), were associated with an increased risk of symptoms. When using a general workplace hygiene score derived from a combination of PPE-use and (good) workplace practice factors an inverse and significant dose-response trend was observed for reporting ≥5 (P < 0.01) and ≥10 symptoms (P < 0.01).

Conclusions

This study has shown that PPE-use and good workplace hygiene are associated with a strongly reduced risk of symptoms of neurotoxicity in solvent-exposed vehicle spray painters.

A field study to determine the effectiveness of several respiratory protection masks on the styrene exposure during lamination activities

PURPOSE OF THE STUDY

The purpose of this study is to examine the effectiveness of several types of personal respiratory protection equipment at styrene exposed laminators under real work place conditions.

SUBJECTS AND METHOD

99 male styrene exposed workers were examined. During their lamination activities the average styrene concentrations in air ranged between 30 to 60 ppm (maximum: 205 ppm). The laminators were followed during an usual workweek from Monday to Thursday. The external styrene exposure was measured by means of passive active carbon badges. The excretion of mandelic acid (MA) and phenyl glyoxylic acid (PGA) in end-of-shift urine samples was used to quantify the internal styrene load. During the work shift some laminators did not use respiratory protection masks. The majority used either a half face mask with active carbon filter or an air purifying respirator.

RESULTS

The respiratory masks were worn during an average between 31% and 72% of the work time. The styrene concentrations of the ambient air were -depending on the activity- in the range of 30 to 60 ppm. The end-of-shift concentrations of MA and PGA in urine samples varied considerably, their means range from 153 to 606 mg/g creatinine. The comparison shows that workers with air purifying respirators experience the lowest internal styrene body burden in spite of high external exposures. Their effectiveness during usual working condition was around 83% whereas the use of half face masks with active carbon filters reduce styrene exposure only of 26% as an average.

CONCLUSIONS

The use of styrene-containing resins in boatbuilding can be associated with increased external styrene exposure of the laminators. During the use of different types of respiratory protection masks it is shown that only the application of air purifying respirators leads to a significant reduction of the internal styrene body burden of 83% when worn during 72% of the total work time. In this way it is possible to comply with or to stay clearly below the biological limit value of 600 mg MA + PGA/g creatinine (BAT-value).

Biological monitoring of benzene exposure during maintenance work in crude oil cargo tanks

We investigated the association between the individual concentrations of benzene in the breathing zone and the concentrations of benzene in the blood and urine among workers maintaining crude oil cargo tanks. Benzene exposure was measured during three consecutive 12h work days among 13 tank workers and 9 unexposed referents (catering section). Blood and urine samples were collected pre-shift on the first day, post-shift on the third day, and pre-next shift on the following morning. The workers used half-mask air-purifying respirators, but not all workers used these systematically. The individual geometric mean benzene exposure in the breathing zone of tank workers over 3 days was 0.15 ppm (range 0.01-0.62 ppm). The tank workers' post-shift geometric mean benzene concentrations were 12.3 nmol/l in blood and 27.0 nmol/l in urine versus 0.7 nmol/l for both blood and urine among the referents. Benzene in the work atmosphere was highly correlated with the internal concentration of benzene both in post-shift blood (r=0.87, P<0.001) and post-shift urine (r=0.90, P<0.001), indicating that the varying use of respirators did not explain much of the variability in absorbed benzene. The results showed that, despite low benzene exposure in this work atmosphere and the use of personal protective equipment to a varying degree, the tank workers had a significant uptake of benzene that correlated highly with benzene exposure. The internal concentration of benzene was higher than expected considering the measured individual benzene exposure, probably due to an extended work schedule of 12h and physical strain during tank work. Control measures should be improved for processes, which impose a potential for increased absorption of benzene upon the workers.

Predictors of occupational exposure to styrene and styrene-7,8-oxide in the reinforced plastics industry

OBJECTIVE

To identify demographic and work related factors that predict blood levels of styrene and styrene-7,8-oxide (SO) in the fibreglass reinforced plastics (FRP) industry.

METHODS

Personal breathing-zone air samples and whole blood samples were collected repeatedly from 328 reinforced plastics workers in the Unuted States between 1996 and 1999. Styrene and its major metabolite SO were measured in these samples. Multivariable linear regression analyses were applied to the subject-specific levels to explain the variation in exposure and biomarker levels.

RESULTS

Exposure levels of styrene were approximately 500-fold higher than those of SO. Exposure levels of styrene and SO varied greatly among the types of products manufactured, with an 11-fold range of median air levels among categories for styrene and a 23-fold range for SO. Even after stratification by job title, median exposures of styrene and SO among laminators varied 14- and 31-fold across product categories. Furthermore, the relative proportions of exposures to styrene and SO varied among product categories. Multivariable regression analyses explained 70% and 63% of the variation in air levels of styrene and SO, respectively, and 72% and 34% of the variation in blood levels of styrene and SO, respectively. Overall, air levels of styrene and SO appear to have decreased substantially in this industry over the last 10-20 years in the US and were greatest among workers with the least seniority.

CONCLUSIONS

As levels of styrene and SO in air and blood varied among product categories in the FRP industry, use of job title as a surrogate for exposure can introduce unpredictable measurement errors and can confound the relation between exposure and health outcomes in epidemiology studies. Also, inverse relations between the intensity of exposure to styrene and SO and years on the job suggest that younger workers with little seniority are typically exposed to higher levels of styrene and SO than their coworkers.