Noise Exposure and Hearing Loss among Workers at a Hammer Forge Company.

The National Institute for Occupational Safety and Health (NIOSH) evaluated continuous and impact noise exposures and hearing loss among workers at a hammer forge company. Full-shift personal noise exposure measurements were collected on forge workers across 15 different job titles; impact noise characteristics and one-third octave band noise levels were assessed at the forge hammers; and 4,750 historic audiometric test records for 483 workers were evaluated for hearing loss trends. Nearly all workers' noise exposures exceeded regulatory and/or recommended exposure limits. Workers working in jobs at or near the hammers had full-shift time-weighted average noise exposures above 100 decibels, A-weighted. Impact noise at the hammers reached up to 148 decibels. Analysis of audiometric test records showed that 82% of workers had experienced a significant threshold shift, as defined by NIOSH, and 63% had experienced a standard threshold shift, as defined by the Occupational Safety and Health Administration (OSHA). All workers with an OSHA standard threshold shift had a preceding NIOSH significant threshold shift which occurred, on average, about 7 years prior. This evaluation highlights forge workers' exposures to high levels of noise, including impact noise, and how their hearing worsened with age and length of employment.

Work-Related Risk Factors for Rotator Cuff Syndrome in a Prospective Study of Manufacturing and Healthcare Workers.

OBJECTIVE: This prospective study assessed the risk of developing rotator cuff syndrome (RCS) with separate or specific combinations of biomechanical exposures measures, controlling for individual confounders. BACKGROUND: Compared with other musculoskeletal disorders, rates of work-related shoulder musculoskeletal disorders have been declining more slowly. METHOD: We conducted up to 2 years of individual, annual assessments of covariates, exposures, and health outcomes for 393 U.S. manufacturing and healthcare workers without RCS at baseline. Task-level biomechanical exposures assessed exposure to forceful exertions (level, exertion rates, duty cycles), vibration, and upper arm postures (flexion, abduction). Hazard ratios (HRs) were calculated with Cox proportional hazard models. RESULTS: We observed 39 incident RCS cases in 694 person-years (incidence rate = 5.62 per 100 person-years). Adjusting for confounders, we found increased risk of incident RCS associated with forceful hand exertions per minute for three upper arm posture tertiles: flexion ≥45° (≥28.2% time, HR = 1.11, CI [1.01, 1.22]), abduction ≥30° (11.9-21.2%-time, HR = 1.18, CI [1.04, 1.34]), and abduction >60° (≥4.8% time, HR = 1.16, CI [1.04, 1.29]). We failed to observe statistically significant effects for other interactions or any separate measures of biomechanical exposure. CONCLUSION: This study highlights the importance of assessing combinations of exposure to forceful repetition and upper arm elevation when developing interventions for preventing RCS. APPLICATION: Based on these results, interventions that reduce exposure to forceful repetition (i.e., lower force levels and/or slower exertion rates) may reduce the risk of RCS, especially when upper arm elevation cannot be avoided.

Temporary and Permanent Auditory Effects Associated with Occupational Coexposure to Low Levels of Noise and Solvents.

This study aimed to assess temporary and permanent auditory effects associated with occupational coexposure to low levels of noise and solvents. Cross-sectional study with 25 printing industry workers simultaneously exposed to low noise (<80 dBA TWA) and low levels of solvents. The control group consisted of 29 industry workers without the selected exposures. Participants answered a questionnaire and underwent auditory tests. Auditory fatigue was measured by comparing the acoustic reflex threshold before and after the workday. Workers coexposed to solvents and noise showed significantly worse results in auditory tests in comparison with the participants in the control group. Auditory brainstem response results showed differences in III−V interpeak intervals (p = 0.046 in right ear; p = 0.039 in left ear). Mean dichotic digits scores (exposed = 89.5 ± 13.33; controls = 96.40 ± 4.46) were only different in the left ear (p = 0.054). The comparison of pre and postacoustic reflex testing indicated mean differences (p = 0.032) between the exposed (4.58 ± 6.8) and controls (0 ± 4.62) groups. This study provides evidence of a possible temporary effect (hearing fatigue) at the level of the acoustic reflex of the stapedius muscle. The permanent effects were identified mainly at the level of the high brainstem and in the auditory ability of binaural integration.

Safe patient handling and mobility (SPHM) for increasingly bariatric patient populations: Factors related to caregivers' self-reported pain and injury.

This study was conducted at 5 Veterans Administration Medical Centers (VAMCs). A cross sectional survey was administered to 134 workers who routinely lift and mobilize patients within their workplaces' safe patient handling and mobility (SPHM) programs, which are mandated in all VAMCs. The survey was used to examine a comprehensive list of SPHM and non-SPHM variables, and their associations with self-reported musculoskeletal injury and pain. Previously unstudied variables distinguished between "bariatric" (≥300 lb or 136 kg) and "non-bariatric" (<300 lb or 136 kg) patient handling. Significant findings from stepwise and logistic regression provide targets for workplace improvements, predicting: lower injury odds with more frequently having sufficient time to use equipment, higher back pain odds with more frequent bariatric handling, lower back pain odds with greater ease in following SPHM policies, and lower odds of upper extremity pain with more bariatric equipment, and with higher safety climate ratings.

Trends in Work-Related Musculoskeletal Disorders From the 2002 to 2014 General Social Survey, Quality of Work Life Supplement.

OBJECTIVE: To update trends in prevalence of back and upper limb musculoskeletal symptoms and risk factors from the 2014 Quality of Work Life (QWL) Survey. METHODS: Quadrennial QWL Surveys, 2002 to 2014 (with N = 1455, 1537, 1019, and 1124 in 2002, 2006, 2010, and 2014 surveys respectively) were analyzed for reports of back pain and pain in arms. RESULTS: In the fourth analysis of this survey, 12-year trends continue to show a decline in back pain and pain in arms. Key physical (heavy lifting, hand movements, very hard physical effort) and psychosocial/work organizational factors (low supervisor support, work is always stressful, not enough time to get work done) remain associated with back and arm pain, with the physical risk factors showing the strongest associations. CONCLUSION: Physical exposure risk factors continue to be strongly associated with low back and arm pain and should be the focus of intervention strategies.

Noise exposures and perceptions of hearing conservation programs among wildland firefighters.

Wildland firefighters are exposed to numerous noise sources that may be hazardous to their hearing. This study examined the noise exposure profiles for 264 wildland firefighters across 15 job categories. All 264 firefighters completed questionnaires to assess their use of hearing protection devices, enrollment in hearing conservation programs, and their overall perception of their noise exposure. Roughly 54% of firefighters' noise exposures exceeded the National Institute for Occupational Safety and Health recommended exposure limit of 85 decibels, A-weighted, over 8 hr, and 32% exceeded the Occupational Safety and Health Administration permissible exposure limit of 90 decibels, A-weighted, over 8 hr. Questionnaire results indicated good agreement between noise exposures and firefighters' perceptions of the noise hazard. Approximately 65% reported that they used some form of hearing protection; however, only 19% reported receiving any proper training regarding the use of hearing protection devices, with the majority of those firefighters relying on earplugs, including electronic and level-dependent earplugs, over earmuffs or other forms of hearing protectors. The results also suggest that improved communication and situational awareness play a greater role in the consistent use of hearing protection devices than other factors such as risk of developing noise-induced hearing loss. The study highlighted the challenges facing wildland firefighters and their management and the need for a comprehensive wildland fire agencies' hearing conservation program especially for firefighters who were exempt based on their occupational designations.

Auditory system dysfunction in Brazilian gasoline station workers.

Objective: To examine the auditory system of Brazilian gasoline station workers using an extensive audiological test battery. Design: This was a cross-sectional study. The audiological evaluation included a questionnaire, pure-tone audiometry, acoustic immittance tests, transient-evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAEs), auditory brainstem response (ABR) and P300 auditory-evoked potentials. Study sample: A total of 77 Brazilian gasoline station workers were evaluated, and their results were compared with those of 36 participants who were not exposed to chemicals or noise at work. The gasoline station employees worked in 18 different gas stations, and the noise area measurements from all gas stations revealed time-weighted averages below 85 dBA. Results: Of the 77 gasoline station workers evaluated, 67.5% had audiometric results within the normal range, but 59.7% reported difficulties in communication in noisy places. Gasoline station workers showed significantly poorer results than non-exposed control participants in one or more conditions of each of the audiological tests used, except P300. Conclusions: The results suggest that the gasoline station workers have both peripheral and central auditory dysfunctions that could be partly explained by their exposure to gasoline.

The relationships between blood lead levels and serum thyroid stimulating hormone and total thyroxine in the third National Health and Nutrition Examination Survey.

Regression analysis was used to estimate and test for relationships between the blood lead concentration and the concentrations of serum thyroid stimulating hormone and serum total thyroxine in adults, 20 years and older, participating in the third National Health and Nutrition Examination Survey. No relationship was found between the blood lead level and the concentration of serum thyroid stimulating hormone. The serum total thyroxine concentration decreased as the blood lead level increased in women, but not in men. The lowest concentration of blood lead at which a relationship could be detected was 2.1 µg/dL and 3.9 µg/dL for the non-pregnant and pregnant women, respectively. Hypothetical mechanisms of the action of lead are discussed.

Field evaluation of onsite near real-time monitors for surface contamination by 5-fluorouracil.

OBJECTIVES: In order to produce near real-time onsite results to detect surface contamination by antineoplastic drugs, the National Institute for Occupational Safety and Health developed monitors for 5-fluorouracil, which use surface wiping and lateral flow immunoassay for measurement. The monitors were tested in the laboratory to assess the sensitivity of detection on laboratory-produced contaminated surfaces. A field evaluation to assess the capability of the monitors to make measurements in healthcare workplaces was carried out in collaboration with a medical device company and the results are presented in this report. METHODS: The 5-fluorouracil monitor was evaluated in areas where oncology drugs were prepared and administered to patients at five different hospitals. The levels of contamination measured with the monitors were compared to levels measured with liquid chromatography-tandem mass spectrometry. RESULTS: The 5-fluorouracil values measured with the liquid chromatography-tandem mass spectrometry ranged from 0 to over 200,000 ng/100 cm2. Measurements by the 5-fluorouracil monitors in the range 10-100 ng/100 cm2 correlated with the liquid chromatography-tandem mass spectrometry. Receiver operating characteristic curves developed for the data indicated that a positive limit of 22 ng/100 cm2 would give an acceptable level of false-positives while retaining most true-positive samples. If the liquid chromatography-tandem mass spectrometry measured greater than 100 ng/100 cm2, then the monitors also measured levels greater than 100 ng/100 cm2 for the majority of samples. CONCLUSION: The data indicate that there are many areas in hospitals that are contaminated with 5-fluorouracil and the monitors will be useful in identifying this contamination.

Associations between urinary biomarkers of polycyclic aromatic hydrocarbon exposure and reproductive function during menstrual cycles in women.

Essentially all women are exposed to polycyclic aromatic hydrocarbons (PAHs), formed during incomplete combustion of organic materials, including fossil fuels, wood, foods, and tobacco. PAHs are ovarian toxicants in rodents, and cigarette smoking is associated with reproductive abnormalities in women. Biomonitoring of hydroxylated PAH (OH-PAH) metabolites in urine provides an integrated measure of exposure to PAHs via multiple routes and has been used to characterize exposure to PAHs in humans. We hypothesized that concentrations of OH-PAHs in urine are associated with reproductive function in women. We recruited women 18-44years old, living in Orange County, California to conduct daily measurement of urinary luteinizing hormone (LH) and estrone 3-glucuronide (E13G) using a microelectronic fertility monitor for multiple menstrual cycles; these data were used to calculate endocrine endpoints. Participants also collected urine samples on cycle day 10 for measurement of nine OH-PAHs. Models were constructed for eight endpoints using a Bayesian mixed modeling approach with subject-specific random effects allowing each participant to act as a baseline for her set of measurements. We observed associations between individual OH-PAH concentrations and follicular phase length, follicular phase LH and E13G concentrations, preovulatory LH surge concentrations, and periovulatory E13G slope and concentration. We have demonstrated the feasibility of using urinary reproductive hormone data obtained via fertility monitors to calculate endocrine endpoints for epidemiological studies of ovarian function during multiple menstrual cycles. The results show that environmental exposure to PAHs is associated with changes in endocrine markers of ovarian function in women in a PAH-specific manner.

Inter-laboratory comparison of three earplug fit-test systems.

The National Institute for Occupational Safety and Health (NIOSH) sponsored tests of three earplug fit-test systems (NIOSH HPD Well-Fit, Michael & Associates FitCheck, and Honeywell Safety Products VeriPRO). Each system was compared to laboratory-based real-ear attenuation at threshold (REAT) measurements in a sound field according to ANSI/ASA S12.6-2008 at the NIOSH, Honeywell Safety Products, and Michael & Associates testing laboratories. An identical study was conducted independently at the U.S. Army Aeromedical Research Laboratory (USAARL), which provided their data for inclusion in this article. The Howard Leight Airsoft premolded earplug was tested with twenty subjects at each of the four participating laboratories. The occluded fit of the earplug was maintained during testing with a soundfield-based laboratory REAT system as well as all three headphone-based fit-test systems. The Michael & Associates lab had the highest average A-weighted attenuations and smallest standard deviations. The NIOSH lab had the lowest average attenuations and the largest standard deviations. Differences in octave-band attenuations between each fit-test system and the American National Standards Institute (ANSI) sound field method were calculated (Attenfit-test - AttenANSI). A-weighted attenuations measured with FitCheck and HPD Well-Fit systems demonstrated approximately ±2 dB agreement with the ANSI sound field method, but A-weighted attenuations measured with the VeriPRO system underestimated the ANSI laboratory attenuations. For each of the fit-test systems, the average A-weighted attenuation across the four laboratories was not significantly greater than the average of the ANSI sound field method. Standard deviations for residual attenuation differences were about ±2 dB for FitCheck and HPD Well-Fit compared to ±4 dB for VeriPRO. Individual labs exhibited a range of agreement from less than a dB to as much as 9.4 dB difference with ANSI and REAT estimates. Factors such as the experience of study participants and test administrators, and the fit-test psychometric tasks are suggested as possible contributors to the observed results.

A meta-analysis of studies investigating the effects of occupational lead exposure on thyroid hormones.

INTRODUCTION: Investigations of the effects of occupational exposure to lead on the concentrations of thyroid hormones in the blood have not produced consistent results. A meta-analysis was performed to assess the effect of occupational exposure to lead on thyroid hormone concentrations using the results from published studies. METHODS: Group means from studies of the thyroid function of persons occupationally exposed to lead were used in a meta-analysis. Differences between the control and exposed groups, and the slopes between thyroid hormone concentrations and log10 blood lead concentrations or duration of exposure to lead were estimated using mixed models. The hormones analyzed were thyroid stimulating hormone, total and free thyroxine, and total and free triiodothyronine. RESULTS: No differences in mean thyroid hormone concentrations were found between the exposed and control groups. No relationships were found between blood lead or the duration of exposure to lead and thyroid hormone concentrations. CONCLUSION: The results of the analysis do not provide evidence for an effect of occupational lead exposure on thyroid function in men. Am. J. Ind. Med. 59:583-590, 2016. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Menstrual cycle perturbation by organohalogens and elements in the Cree of James Bay, Canada.

Persistent organohalogens (POHs) and metals have been linked to alterations in menstrual cycle function and fertility in humans. The Cree First Nations people living near James Bay in Ontario and Quebec, Canada, have elevated levels of POHs, mercury and lead compared to other Canadians. The present study examines the interrelationships between selected POHs and elements on menstrual cycle function in these Cree women. Menstrual cycle characteristics were derived from structured daily diaries and endocrine measurements from daily urine samples collected during one cycle for 42 women age 19-42. We measured 31 POHs in blood plasma and 18 elements in whole blood, for 31 of the participants. POHs and elements detected in ≥ 70% of the participants were transformed by principal component (PC) analysis to reduce the contaminant exposure data to fewer, uncorrelated PCA variables. Multiple regression analysis revealed that, after adjusting for confounders, PC-3 values showed significant negative association with cycle length, after adjusting for confounders (p = 0.002). PC-3 accounted for 9.2% of the variance and shows positive loadings for cadmium, selenium, and PBDE congeners 47 and 153, and a negative loading for copper. Sensitivity analysis of the model to quantify likely effect sizes showed a range of menstrual cycle length from 25.3 to 28.3 days using the lower and upper 95% confidence limits of mean measured contaminant concentrations to predict cycle length. Our observations support the hypothesis that the menstrual cycle function of these women may be altered by exposure to POHs and elements from their environment.

Serious injury and fatality investigations involving pneumatic nail guns, 1985-2012.

BACKGROUND: This article examines serious and fatal pneumatic nail gun (PNG) injury investigations for workplace, tool design, and human factors relevant to causation and resulting OS&H authorities' responses in terms of citations and penalties. METHODS: The U.S. Occupational Safety and Health Administration (OSHA) database of Fatality and Catastrophe Investigation Summaries (F&CIS) were reviewed (1985-2012) to identify n = 258 PNG accidents. RESULTS: 79.8% of investigations, and 100% of fatalities, occurred in the construction industry. Between 53-71% of injuries appear to have been preventable had a safer sequential trigger tool been used. Citations and monetary penalties were related to injury severity, body part injured, disabling of safety devices, and insufficient personal protective equipment (PPE). CONCLUSIONS: Differences may exist between construction and other industries in investigators interpretations of PNG injury causation and resulting citations/penalties. Violations of PPE standards were penalized most severely, yet the preventive effect of PPE would likely have been less than that of a safer sequential trigger.

Further Trends in Work-Related Musculoskeletal Disorders: A Comparison of Risk Factors for Symptoms Using Quality of Work Life Data From the 2002, 2006, and 2010 General Social Survey.

OBJECTIVE: To report trends for the risk of musculoskeletal disorders. METHODS: Three Quality of Work Life surveys examine the risk factors for musculoskeletal disorders. RESULTS: Findings similar for several risk factors, but differences across the reporting years may reflect economic conditions. Respondent numbers in 2010 were reduced, some risk factors had pattern changes, and there were sex and age differences. Trend analysis showed most significant changes were for the "work fast" risk factor. New 2010 "physical effort" item showed sex differences, and items reflective of total worker health showed strong associations with "back pain" and "pain in arms." CONCLUSIONS: Intervention strategies should focus on physical exposures and psychosocial risk factors (work stress, safety climate, job satisfaction, supervisor support, work fast, work freedom, work time) that have been consistently related to reports of musculoskeletal disorders. Economic conditions will influence some psychosocial risk factors.

Time-related increase in urinary testosterone levels and stable semen analysis parameters after bariatric surgery in men.

The aim of this prospective cohort study was to determine the time-course in androgen and semen parameters in men after weight loss associated with bariatric surgery. Six men aged 18-40 years, meeting National Institutes of Health bariatric surgery guidelines, were followed between 2005 and 2008. Study visits took place at baseline, then 1, 3, 6 and 12 months after surgery. All men underwent Roux-en-y gastric bypass (RYGB). At each visit, biometric, questionnaire, serum, and urinary specimens and seman analysis were collected. Urinary integrated total testosterone levels increased significantly (P < 0.0001) by 3 months after surgery, and remained elevated throughout the study. Circulating testosterone levels were also higher at 1 and 6 months after surgery, compared with baseline. Serum sex hormone-binding globulin levels were significantly elevated at all time points after surgery (P < 0.01 to P = 0.02). After RYGB surgery, no significant changes occurred in urinary oestrogen metabolites (oestrone 3-glucuronide), serum oestradiol levels, serial semen parameters or male sexual function by questionnaire. A threshold of weight loss is necessary to improve male reproductive function by reversing male hypogonadism, manifested as increased testosterone levels. Further serial semen analyses showed normal ranges for most parameters despite massive weight loss.

Efficacy of the revised NIOSH lifting equation to predict risk of low-back pain associated with manual lifting: a one-year prospective study.

OBJECTIVE: The objective was to evaluate the efficacy of the Revised National Institute for Occupational Safety and Health (NIOSH) lifting equation (RNLE) to predict risk of low-back pain (LBP). BACKGROUND: In 1993, NIOSH published the RNLE as a risk assessment method for LBP associated with manual lifting. To date, there has been little research evaluating the RNLE as a predictor of the risk of LBP using a prospective design. METHODS: A total of 78 healthy industrial workers' baseline LBP risk exposures and self-reported LBP at one-year follow-up were investigated. The composite lifting index (CLI), the outcome measure of the RNLE for analyzing multiple lifting tasks, was used as the main risk predictor. The risk was estimated using the mean and maximum CLI variables at baseline and self-reported LBP during the follow-up. Odds ratios (ORs) were calculated using a logistic regression analysis adjusted for covariates that included personal factors, physical activities outside of work, job factors, and work-related psychosocial characteristics. RESULTS: The one-year self-reported LBP incidence was 32.1%. After controlling for history of prior LBP, supervisory support, and job strain, the categorical mean and maximum CLI above 2 had a significant relationship (OR = 5.1-6.5) with self-reported LBP, as compared with the CLI below or equal to I. The correlation between the continuous CLI variables and LBP was unclear. CONCLUSIONS: The CLI > 2 threshold may be useful for predicting self-reported LBP. Research with a larger sample size is needed to clarify the exposure-response relationship between the CLI and LBP.

The relationships between pesticide metabolites and neurobehavioral test performance in the third National Health and Nutrition Examination Survey.

Regression analysis was used to estimate and test for relationships between urinary pesticide metabolites and neurobehavioral test performance in adults, 20 to 59 years old, participating in the third National Health and Nutrition Examination Survey. The 12 pesticide metabolites included 2 naphthols, 8 phenols, a phenoxyacetic acid, and a pyridinol. The 3 neurobehavioral tests included in the survey were simple reaction time, symbol-digit substitution, and serial digit learning. As the 2,4-dichlorophenol, 2,5-dichlorophenol, and the pentachlorophenol concentrations increased, performance on the serial digit learning test improved. As the 2,5-dichlorophenol concentration increased, performance on the symbol-digit substitution test improved. At low concentrations, the parent compounds of these metabolites may act at acetylcholine and γ-aminobutyric acid synapses in the central nervous system to improve neurobehavioral test performance.

Effects of gestational and lactational exposure to heptachlor epoxide on age at puberty and reproductive function in men and women.

BACKGROUND: For 15 months in 1981-1982, the commercial milk supply on the Hawaiian island of Oahu was contaminated with heptachlor epoxide, a metabolite of the insecticide heptachlor, resulting in gestational and/or lactational exposure to offspring of women who drank cow milk during that period. OBJECTIVE: To determine whether gestational and lactational exposure to heptachlor epoxide alters reproductive function and age at puberty in men or women. METHODS: 457 participants were recruited from a prior high school enrollment sampling frame of 20,000 adults born during 1981-1982 who lived on Oahu since at least first grade. Number of glasses of cow milk consumed weekly by the mother during the participant's gestation was used as a surrogate measure of heptachlor epoxide exposure. Reproductive function measures included semen analyses; reproductive hormones or their metabolites in daily urine specimens for one menstrual cycle; serum reproductive hormone levels in both sexes; and reported ages of onset for pubertal milestones. RESULTS: We observed no strong associations of heptachlor epoxide exposure during gestation and lactation with reproductive endpoints. In females, heptachlor epoxide exposure was associated with longer luteal phase length and slower drop in the ratio of estradiol to progesterone metabolites after ovulation. In males, heptachlor epoxide exposure was weakly associated with higher serum follicle stimulating hormone and luteinizing hormone concentrations, but no dose-response relationship was apparent. CONCLUSIONS: The results provide limited evidence that gestational and lactational exposure to heptachlor epoxide, due to milk contamination on Oahu in 1981-1982, resulted in clinically significant disturbances of reproductive function in men or women.

Finger Tendon Travel Associated with Sequential Trigger Nail Gun Use.

BACKGROUND: Pneumatic nail guns used in wood framing are equipped with one of two triggering mechanisms. Sequential actuation triggers have been shown to be a safer alternative to contact actuation triggers because they reduce traumatic injury risk. However, the sequential actuation trigger must be depressed for each individual nail fired as opposed to the contact actuation trigger, which allows the trigger to be held depressed as nails are fired repeatedly by bumping the safety tip against the workpiece. As such, concerns have been raised about risks for cumulative trauma injury, and reduced productivity, due to repetitive finger motion with the sequential actuation trigger. PURPOSE: This study developed a method to predict cumulative finger flexor tendon travel associated with the sequential actuation trigger nail gun from finger joint kinematics measured in the trigger actuation and productivity standards for wood-frame construction tasks. METHODS: Finger motions were measured from six users wearing an instrumented electrogoniometer glove in a simulation of two common framing tasks-wall building and flat nailing of material. Flexor tendon travel was calculated from the ensemble average kinematics for an individual nail fired. RESULTS: Finger flexor tendon travel was attributable mostly to proximal interphalangeal and distal interphalangeal joint motion. Tendon travel per nail fired appeared to be slightly greater for a wall-building task than a flat nailing task. The present study data, in combination with construction industry productivity standards, suggest that a high-production workday would be associated with less than 60 m/day cumulative tendon travel per worker (based on 1700 trigger presses/day). CONCLUSION AND APPLICATIONS: These results suggest that exposure to finger tendon travel from sequential actuation trigger nail gun use may be below levels that have been previously associated with high musculoskeletal disorder risk.