Diesel particulate matter (DPM) is a common and well-known health hazard in the mining environment. The regulatory method for monitoring both the organic and elemental carbon (OC, EC) portions of DPM is a laboratory-based thermal-optical method with a typical turnaround time of one week. In order to evaluate exposure levels and take corrective action prior to overexposure, a portable real-time device capable of quantifying both OC and EC is needed. To that end, researchers from the National Institute for Occupational Safety and Health (NIOSH) designed and tested the feasibility of a device based on bandpass optical filters that target key infrared wavelengths associated with DPM and its spectroscopic baseline. The resulting device, referred to here as a non-dispersive infrared (NDIR) spectrometer could serve as the basis of a cost-effective, field-portable alternative to the laboratory thermal-optical method. The limits of quantification (LOD) indicate that the NDIR spectrometer can quantify EC, OC, and TC provided they are present at 20, 37, and 46 μg/m3 or more, respectively. In the event that the NDIR spectrometer is integrated with a sampler and filter tape the LOD is estimated to be reduced to 13, 7, and 10 μg/m3 for EC, OC, and TC, respectively. These LOD estimates assume a face velocity of 59 cm/s and a sampling time of 30 min. ©, This work was authored as part of the Contributor's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 USC. 105, no copyright protection is available for such works under US Law.

OBJECTIVE: Inhalation of diesel exhaust (DE) has been shown to be an occupational hazard in the transportation, mining, and gas and oil industries. DE also contributes to air pollution, and therefore, is a health hazard to the general public. Because of its effects on human health, changes have been made to diesel engines to reduce both the amounts of particulate matter and volatile fumes they generate. The goal of the current study was to examine the effects of inhalation of diesel exhaust. MATERIALS AND METHODS: The study presented here specifically examines the effects of exposure to 0.2 and 1.0 mg/m(3) DE or filtered air (6h/d for 4 d) on measures of peripheral and cardio-vascular function, and biomarkers of heart and kidney dysfunction in male rats. A Tier 2 engine used in oil and gas fracking operations was used to generate the diesel exhaust. RESULTS: Exposure to 0.2 mg/m(3) DE resulted in an increase in blood pressure 1d following the last exposure, and increases in dobutamine-induced cardiac output and stroke volume 1 and 27d after exposure. Changes in peripheral vascular responses to norepinephrine and acetylcholine were minimal as were changes in transcript expression in the heart and kidney. Exposure to 1.0 mg/m(3) DE did not result in major changes in blood pressure, measures of cardiac function, peripheral vascular function or transcript expression. DISCUSSION AND CONCLUSIONS: Based on the results of this study, we suggest that exposure to DE generated by a Tier 2 compliant diesel engine generates acute effects on biomarkers indicative of cardiovascular dysfunction. Recovery occurs quickly with most measures of vascular/cardiovascular function returning to baseline levels by 7d following exposure.

Diesel exhaust (DE) is an air pollutant containing gaseous compounds and particulate matter. Diesel engines are common on gas extraction and oil sites, leading to complex DE exposure to a broad range of compounds through occupational settings. The US EPA concluded that short-term exposure to DE leads to allergic inflammatory disorders of the airways. To further evaluate the immunotoxicity of DE, the effects of whole-body inhalation of 0.2 and 1 mg/m(3) DE (total carbon; 6 h/d for 4 days) were investigated 1-, 7-, and 27-days post exposure in Sprague-Dawley rats using an occupationally relevant exposure system. DE exposure of 1 mg/m(3) increased total cellularity, number of CD4+ and CD8+ T-cells, and B-cells at 1 d post-exposure in the lung lymph nodes. At 7 d post-exposure to 1 mg/m(3), cellularity and the number of CD4+ and CD8+ T-cells decreased in the LLNs. In the bronchoalveolar lavage, B-cell number and frequency increased at 1 d post-exposure, Natural Killer cell number and frequency decreased at 7 d post-exposure, and at 27 d post-exposure CD8+ T-cell and CD11b+ cell number and frequency decreased with 0.2 mg/m(3) exposure. In the spleen, 0.2 mg/m(3) increased CD4+ T-cell frequency at 1 and 7 d post-exposure and at 27 d post-exposure increased CD4+ and CD8+ T-cell number and CD8+ T-cell frequency. B-cells were the only immune cell subset altered in the three tissues (spleen, LLNs, and BALF), suggesting the induction of the adaptive immune response. The increase in lymphocytes in several different organ types also suggests an induction of a systemic inflammatory response occurring following DE exposure. These results show that DE exposure induced modifications of cellularity of phenotypic subsets that may impair immune function and contribute to airway inflammation induced by DE exposure in rats.

Untreated syphilis can lead to ocular syphilis, otosyphilis, and neurosyphilis, conditions resulting from Treponema pallidum infection of the eye, inner ear, or central nervous system. During March-July 2022, Michigan public health officials identified a cluster of ocular syphilis cases. The public health response included case investigation, partner notification, dissemination of health alerts, patient referral to a public health clinic for diagnosis and treatment, hospital care coordination, and specimen collection for T. pallidum molecular typing. Five cases occurred among southwest Michigan women, all of whom had the same male sex partner. The women were aged 40-60 years, HIV-negative, and identified as non-Hispanic White race; the disease was staged as early syphilis, and all patients were hospitalized and treated with intravenous penicillin. The common male sex partner was determined to have early latent syphilis and never developed ocular syphilis. No additional transmission was identified after the common male partner's treatment. Due to lack of genetic material in limited specimens, syphilis molecular typing was not possible. A common heterosexual partner in an ocular syphilis cluster has not been previously documented and suggests that an unidentified strain of T. pallidum might have been associated with increased risk for systemic manifestations of syphilis. A high index of clinical suspicion and thorough sexual history are critical to diagnosing ocular syphilis, otosyphilis, and neurosyphilis. Coordination of disease surveillance with disease intervention specialist investigation and treatment referral can interrupt syphilis transmission.

INTRODUCTION: People Living with HIV (PLWH) have higher prevalence of adverse COVID-19 outcomes, and many reside in socially vulnerable communities. Our aim is to evaluate how engagement in HIV care may increase vaccination likelihood. METHODS: Michigan HIV surveillance data were extracted from the Enhanced HIV/AIDS Reporting System (eHARS) and matched at the person-level to COVID-19 vaccination records from the Michigan Care Improvement Registry (MCIR) (through December 31, 2021 (n=15,537)). Based on residential census tract, we classified PLWH into quartiles (<25th percentile (least vulnerable), 25th to <50th, 50th to <75th, ≥75th (most vulnerable)) of the 2018 CDC Social Vulnerability Index 1. Using log binomial regression, we estimated the relative prevalence of COVID-19 vaccine series initiation among PLWH by quartile of social vulnerability and Ryan White participation; models were adjusted for covariates. RESULTS: By December 31, 2021, 67% of PLWH in Michigan had initiated a COVID-19 vaccine series; 47% resided in an area deemed most vulnerable and 54% had participated in Ryan White services. Compared to PLWH in the most vulnerable quartile, those who resided in least vulnerable quartiles had higher prevalence of vaccine initiation (Prevalence Ratio (95% Confidence Interval): 1.67 (1.50, 1.86). Participants in Ryan White had greater prevalence of initiation (1.52 (1.42, 1.62) compared to those who were not participants; initiation remained higher when adjusted for covariates including social vulnerability quartile. CONCLUSION: Ryan White participation was associated with increased COVID-19 vaccine initiation regardless of community-level vulnerability. Wraparound services may be key in vaccine promotion interventions in this vulnerable population.

Atmospheric monitoring systems (AMS) are required when using air from conveyor belt entries to ventilate working sections in U.S. underground coal mines. AMS technology has the potential to increase fire safety mine-wide, but research is needed to determine the detection and response times for fires of a variety of combustible materials. To evaluate the potential of an AMS for fire detection in other areas of a coal mine, a series of full-scale fire experiments were conducted to determine detection and response times from fires of different combustible materials that are found in U.S. underground coal mines, including high- and low-volatility coals, conveyor belts, brattice materials, different types of wood, diesel fuel, and a foam sealant. These experiments were conducted in the Safety Research Coal Mine (SRCM) of the U.S. National Institute for Occupational Safety and Health (NIOSH) located in Pittsburgh, PA, using a commercially available AMS that is typical of current technology. The results showed that through proper selection of sensors and their locations, a mine-wide AMS can provide sufficient early fire warning times and improve the health and safety of miners.

BACKGROUND: The Diesel Exhaust in Miners Study (DEMS) was an important contributor to the International Agency for Research on Cancer reclassification of diesel exhaust as a Group I carcinogen and subsequent risk assessment. We extended the DEMS cohort follow-up by 18 y and the nested case-control study to include all newly identified lung cancer deaths and matched controls (DEMS II), nearly doubling the number of lung cancer deaths. OBJECTIVE: Our purpose was to characterize the exposure-response relationship with a focus on the effects of timing of exposure and exposure cessation. METHODS: We conducted a case-control study of lung cancer nested in a cohort of 12,315 workers in eight nonmetal mines (376 lung cancer deaths, 718 controls). Controls were selected from workers who were alive when the case died, individually matched on mine, sex, race/ethnicity, and birth year (within 5 y). Based on an extensive historical exposure assessment, we estimated respirable elemental carbon (REC), an index of diesel exposure, for each cohort member. Odds ratios (ORs) were estimated by conditional regression analyses controlling for smoking and other confounders. To evaluate time windows of exposure, we evaluated the joint OR patterns for cumulative REC within each of four preselected exposure time windows,  < 5, 5-9, 10-19, and  ≥ 20 y prior to death/reference date, and we evaluated the interaction of cumulative exposure across time windows under additive and multiplicative forms for the joint association. RESULTS: ORs increased with increasing 15-y lagged cumulative exposure, peaking with a tripling of risk for exposures of  ∼ 950 to < 1,700 μg/m3-y [OR = 3.23; 95% confidence interval (CI): 1.47, 7.10], followed by a plateau/decline among the heavily exposed (OR = 1.85; 95% CI: 0.85, 4.04). Patterns of risk by cumulative REC exposure varied across four exposure time windows (phomogeneity < 0.001), with ORs increasing for exposures accrued primarily 10-19 y prior to death (ptrend < 0.001). Results provided little support for a waning of risk among workers whose exposures ceased for  ≥ 20 y. CONCLUSION: DEMS II findings provide insight into the exposure-response relationship between diesel exhaust and lung cancer mortality. The pronounced effect of exposures occurring in the window 10-19 y prior to death, the sustained risk 20 or more years after exposure ceases, and the plateau/decline in risk among the most heavily exposed provide direction for future research on the mechanism of diesel-induced carcinogenesis in addition to having important implications for the assessment of risk from diesel exhaust by regulatory agencies. https://doi.org/10.1289/EHP11980.

We investigated the suitability of the graphitic carbon (GC) content of diesel particulate matter (DPM), measured using Raman spectroscopy, as a surrogate measure of elemental carbon (EC) determined by thermal optical analysis. The Raman spectra in the range of 800-1800 cm(-1) (including the D mode at ∼1322 cm(-1) and the G mode at ∼1595 cm(-1)) were used for GC identification and quantification. Comparison of the Raman spectra for two certified DPM standards (NIST SRM 1650 and SRM 2975), two types of diesel engine exhaust soot, and three types of DPM-enriched workplace aerosols show that the uncertainty of GC quantification based on the D peak height, G peak height, and the total peak area below D and G peaks was about 6.0, 6.7, and 6.9%, respectively. The low uncertainty for different aerosol types suggested possible use of GC as a surrogate measure of EC in workplace atmospheres. A calibration curve was constructed using two laboratory-aerosolized DPM standards to describe the relationship between GC measured by a portable Raman spectrometer and the EC concentration determined by NIOSH Method 5040. The calibration curve was then applied to determine GC-based estimates of the EC contents of diesel engine exhaust samples from two vehicles and seven air samples collected at a hydraulic fracturing worksite. The GC-EC estimates obtained through Raman measurements agreed well with those found by NIOSH Method 5040 for the same samples at EC filter loadings below 2.86 μg/cm(2). The study shows that using an appropriate sample collection method that avoids high filter mass loadings, onsite measurement of GC by a portable or hand-held Raman spectrometer can provide a useful indicator of EC in workplace aerosol.

The results of diesel particulate matter (DPM) monitoring were used by the underground mining industry to mitigate adverse effects of exposure to DPM. NIOSH Method 5040, currently used for ambient and personal exposure monitoring, does not provide needed real-time information. The objective of this study is to develop a methodology for continuous monitoring of DPM concentrations in an underground environment, founded on the application of the Dekati electrical particle sensor (DePS). The DePS, which measures concentrations of submicron aerosol in real time using a diffusion-charging sensor, was evaluated by comparing the results of the concurrent measurements with reference methods at several locations downstream of the diesel-powered equipment. The DePS results were found to correlate well to those obtained by reference methods. However, it was found that dependence of the response on the physical and chemical properties of aerosols necessitates site-specific correlation factors for the targeted matrices. The site-specific factors for number and mass of diesel aerosols were derived using the results of concurrent measurements with TSI NanoScan, FLIR Airtec, and carbon analyses performed on the concurrently collected filter samples. The results showed that methodology based on compensated DePS measurements would be suitable for continuous monitoring of DPM in underground mining operations. © 2022, Society for Mining, Metallurgy & Exploration Inc.

Air pollution is a known environmental health hazard. A major source of air pollution includes diesel exhaust (DE). Initially, research on DE focused on respiratory morbidities; however, more recently, exposures to DE have been associated with neurological developmental disorders and neurodegeneration. In this study, we investigated the effects of sub-chronic inhalation exposure to DE on neuroinflammatory markers in two inbred mouse strains and both sexes, including whole transcriptome examination of the medial prefrontal cortex. We exposed aged male and female C57BL/6J (B6) and DBA/2J (D2) mice to DE, which was cooled and diluted with HEPA-filtered compressed air for 2 h per day, 5 days a week, for 4 weeks. Control animals were exposed to HEPA-filtered air on the same schedule as DE-exposed animals. The prefrontal cortex was harvested and analyzed for proinflammatory cytokine gene expression (Il1&#223;, Il6, Tnfa) and transcriptome-wide response by RNA-seq. We observed differential cytokine gene expression between strains and sexes in the DE-exposed vs. control-exposed groups for Il1&#223;, Tnfa, and Il6. For RNA-seq, we identified 150 differentially expressed genes between air and DE treatment related to natural killer cell-mediated cytotoxicity per Kyoto Encyclopedia of Genes and Genomes pathways. Overall, our data show differential strain-related effects of DE on neuroinflammation and neurotoxicity and demonstrate that B6 are more susceptible than D2 to gene expression changes due to DE exposures than D2. These results are important because B6 mice are often used as the default mouse model for DE studies and strain-related effects of DE neurotoxicity warrant expanded studies.

Numerous health and safety hazards exist at U.S. onshore oil and gas extraction worksites. Higher fatal injury rates have been reported among drilling and servicing companies, which are more likely to employ workers in construction and extraction occupations, compared to operators that employ more workers in management and office and administrative support roles. However, there is little information describing the extent to which workers encounter these hazards, are provided hazard mitigation strategies by their employers, or use personal protective equipment (PPE). A cross-sectional survey of 472 U.S. oil and gas extraction workers was conducted to identify and characterize factors related to on-the-job fatalities, injuries, and illnesses and determine the health and safety concerns of workers. Workers were employed by servicing companies (271/472, 57.4%), drilling contractors (106/472, 22.5%), and operators (95/472, 20.1%). The likelihood of contact with hazardous substances varied by substance and company type. Drilling and servicing employees had significantly higher odds of self-reported contact with pipe dope (OR(drilling)=10.07, 95% CI: 1.74-63.64; OR(servicing)=5.95, 95% CI: 2.18-18.34), diesel exhaust (OR(drilling)=2.28, 95% CI: 1.15-5.05; OR(servicing)=4.93, 95% CI: 2.73-10.32), and drilling mud (OR(drilling)=24.36, 95% CI: 4.45-144.69; OR(servicing)=3.48, 95% CI: 1.24-12.20), compared to operators. Safety policies, programs, and trainings were commonly reported by workers, although substance-specific training (e.g., respirable crystalline silica hazards) was less common. Differences in self-reported employer PPE requirements and worker use of PPE when needed or required for safety highlight a need for novel strategies to improve use of PPE. Overall, this study highlights differences in work conditions by company type and uncovers gaps in employer administrative controls and PPE use.

Mine equipment fires remain as one of the most concerning safety issues in the mining industry, and most equipment fires were caused by hot surface ignitions. Detailed experimental investigations were conducted at the NIOSH Pittsburgh Mining Research Division on hot surface ignition of liquid fuels under ventilation in a mining environment. Three types of metal surface materials (stainless steel, cast iron, carbon steel), three types of liquids (diesel fuel, hydraulic fluid, engine oil), four air ventilation speeds (0, 0.5, 1.5, 3 m/s) were used to study the hot surface ignition probability under these conditions. Visual observation and thermocouples attached on the metal surface were used to indicate the hot surface ignition from the measured temperatures. Results show that the type of metal has a noticeable effect on the hot surface ignition, while ventilation speed has a mixed influence on ignition. Different types of liquid fuels also show different ranges of ignition temperatures. Results from this work can be used to help understand equipment mine fires and develop mitigation strategies.

BACKGROUND: Shigella species, which cause acute diarrheal disease, are transmitted via fecal-oral and sexual contact. To better understand the overlapping populations affected by Shigella infections and sexually transmitted infections (STIs) in the United States, we examined the occurrence of reported STIs within 24 months among shigellosis case-patients. METHODS: Culture-confirmed Shigella cases diagnosed during 2007-2016 among residents of six U.S. jurisdictions were matched to reports of STIs (chlamydia, gonorrhea, and all stages of syphilis) diagnosed 12 months before or after the shigellosis case. We examined epidemiologic characteristics and reported temporal trends of Shigella cases by sex and species. RESULTS: During 2007-2016, 10,430 shigellosis cases were reported. The annual number of reported shigellosis cases across jurisdictions increased 70%, from 821 cases in 2007 to 1,398 cases in 2016; males saw a larger increase compared to females. Twenty percent of male shigellosis case-patients had an STI reported in the reference period, versus 4% of female case-patients. The percentage of male shigellosis case-patients with an STI increased from 11% (2007) to 28% (2016); the overall percentage among females remained low. CONCLUSIONS: We highlight the substantial proportion of males with shigellosis who were diagnosed with STIs within 24 months and the benefit of matching data across programs. STI screening may be warranted for male shigellosis case-patients.

The case study was conducted in an underground coal mine to characterize submicron aerosols at a continuous miner (CM) section, assess the concentrations of diesel aerosols at the longwall (LW) section, and assess the exposures of selected occupations to elemental carbon (EC) and total carbon (TC). The results show that aerosols at the CM sections were a mixture of aerosols freshly generated at the outby portion of the CM section and those generated in the main drifts that supply fresh air to the section. The relatively low ambient concentrations and personal exposures of selected occupations suggest that currently applied control strategies and technologies are relatively effective in curtailing exposures to diesel aerosols. Further reductions in EC and TC concentrations and personal exposures to those would be possible by more effective curtailment of emissions from high-emitting light duty (LD) vehicles. 2022, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.

Mining vehicle manufacturers are developing lithium-ion (Li-ion) battery electric vehicles as an alternative to diesel-powered vehicles. In gassy underground mines, explosion-proof (XP) enclosures are commonly used to enclose electrical ignition sources to prevent propagation of an internal methane-air explosion to a surrounding explosive atmosphere. Li-ion batteries can create pressurized explosions within sealed enclosures due to thermal runaway (TR). NIOSH researchers measured TR pressures of nickel manganese cobalt (NMC) cathode type 18650 Li-ion cells, model MH1, as a function of free space within sealed enclosures and observed an inverse power relationship. TR pressure-rise rates, gas quantities, and temperatures were also measured. A confined NMC cell with 92.5 mL of free space produced 232 bar of pressure, far exceeding minimum pressure containment specifications for conventional XP enclosures. Approximately 287 times the cell volume of free space would be needed to reduce the TR pressure of these cells to 8.62 barg (125 psig) per U.S. Code of Federal Regulations, Title 30, Part 18. The NMC cell TR pressures were significantly higher than those measured previously for iron phosphate cathode Li-ion cells under comparable confinement conditions. 2022

INTRODUCTION: Disease intervention specialists (DIS) prevent syphilis by assuring treatment for patients' sex partners through partner notification (PN). Different interpretations of how to measure partners treated due to DIS efforts complicates PN evaluation. We measured PN impact by counting partners treated for syphilis after DIS interviewed the patient. METHODS: We reviewed data from early syphilis cases reported during 2015-2017 in seven jurisdictions. We compared infected partners brought to treatment using: 1) DIS-assigned disposition codes or 2) all infected partners treated 0-90 days after the patient's interview (adjusted treatment estimate). Stratified analyses assessed patient characteristics associated with the adjusted treatment estimate. RESULTS: DIS interviewed 23,613 patients who reported 20,890 partners with locating information. Many of the 3,569 (17.1%) partners classified by DIS as brought to treatment were treated before the patient was interviewed. There were 2,359 (11.3%) partners treated 0-90 days after the patient's interview. Treatment estimates were more consistent between programs when measured using our adjusted estimates (range 6.1%-14.8% per patient interviewed) compared to DIS-assigned disposition (range 6.1%-28.3%). Treatment of >1 partner occurred after 9.0% of interviews and was more likely if the patient was a woman (17.9%), aged <25 years (12.6%), interviewed ≤7 days from diagnosis (13.9%), HIV negative (12.6%), or had no reported history of syphilis (9.8%). CONCLUSIONS: Counting infected partners treated 0-90 days after interview reduced variability in reporting and facilitates quality assurance. Identifying programs and DIS who are particularly good at finding and treating partners could improve program impact.

The U.S. COVID-19 vaccination program launched on December 14, 2020. The Advisory Committee on Immunization Practices recommended prioritizing COVID-19 vaccination for specific groups of the U.S. population who were at highest risk for COVID-19 hospitalization and death, including adults aged ≥75 years*; implementation varied by state, and eligibility was gradually expanded to persons aged ≥65 years beginning in January 2021. By April 19, 2021, eligibility was expanded to all adults aged ≥18 years nationwide.(†) To assess patterns of COVID-19 vaccination coverage among U.S. adults, CDC analyzed data submitted on vaccinations administered during December 14, 2020-May 22, 2021, by age, sex, and community-level characteristics. By May 22, 2021, 57.0% of persons aged ≥18 years had received ≥1 COVID-19 vaccine dose; coverage was highest among persons aged ≥65 years (80.0%) and lowest among persons aged 18-29 years (38.3%). During the week beginning February 7, 2021, vaccination initiation among adults aged ≥65 years peaked at 8.2%, whereas weekly initiation among other age groups peaked later and at lower levels. During April 19-May 22, 2021, the period following expanded eligibility to all adults, weekly initiation remained <4.0% and decreased for all age groups, including persons aged 18-29 years (3.6% to 1.9%) and 30-49 years (3.5% to 1.7%); based on the current rate of weekly initiation (as of May 22), younger persons will not reach the same levels of coverage as older persons by the end of August. Across all age groups, coverage (≥1 dose) was lower among men compared with women, except among adults aged ≥65 years, and lower among persons living in counties that were less urban, had higher social vulnerabilities, or had higher percentages of social determinants of poor health. Continued efforts to improve vaccination confidence and alleviate barriers to vaccination initiation, especially among adults aged 18-49 years, could improve vaccination coverage.

Since 2010, reported chlamydia and gonorrhea rates decreased among Black women aged 15-19 years and were stable for Black women 20-24 in the United States. Rates increased for older Black women 25-39 and all White women. The Black:White rate ratio decreased across age groups. We examined whether trends in reported rates reflected changing prevalence or changing screening. We analyzed trends in reported chlamydia and gonorrhea rates during 2010 to 2018 among women in the United States aged 15-39 years by age and race/ethnicity subgroup, state, and reporting source. Most jurisdictions reported decreased chlamydia and gonorrhea rates among Black teens and increased rates among White teens and older women. Between 2010 and 2018, public clinics reported fewer cases, especially among young Black women, that were not restored by increases elsewhere. We reviewed literature on trends in screening, prevalence, and sequelae. Family planning clinics annual reports showed chlamydia tests among women <25 decreased by 541,573 tests (-38%) in 2018 compared with 2010 and the number of women visiting STD clinics had decreased 50% by 2016 compared with 2010. Prevalence of chlamydia in a sentinel population (Job Corps) was unchanged for Black women <25 and increased for Whites 20-24. Sequelae trends using data from a large all-payer ED database were mixed: PID decreased while ectopic pregnancy increased. Decreases in testing at public clinics likely missed diagnoses among young Black women, a group traditionally at highest risk, and in need of more testing. Innovative approaches to screening are needed.

A method for the quantification of airborne organic carbon (OC) and elemental carbon (EC) within aerosolized diesel particulate matter (DPM) is described in this article. DPM is a known carcinogen encountered in many industrial workplaces (notably mining) and in the ambient atmosphere. The method described here collects DPM particles onto a quartz fiber filter, after which reflection-mode infrared spectra are measured on a mid-infrared Fourier transform (FT-IR) spectrometer. Several infrared absorption bands are investigated for their efficacy in quantifying OC and EC. The thermo-optical (T-O) method is used to calibrate a linear regression model to predict OC and EC from the infrared spectra. The calibrated model, generated from laboratory DPM samples, is then utilized to quantify OC and EC in mine samples obtained from two metal mine locations under a variety of operating conditions. The feasibility of further improving these results by partial least squares (PLS) regression was investigated. A single calibration that is broadly applicable would be considered an improvement over currently available portable instruments, which require aerosol-specific calibration.

Diesel particulate matter (DPM) is considered carcinogenic to humans by the International Agency for Research on Cancer (IARC), and mine workers have some of the highest exposures to DPM in the USA. Therefore, mines have been developing control strategies for reducing DPM exposures of mine workers. Many of these strategies include engineering and administrative controls. In addition to these types of controls, a respirator program is used at some mines to provide further protection to mine workers where elevated concentrations of DPM exist. However, sometimes mine workers may feel restricted by the use of a half-mask respirator or inconvenienced by the requirement to remove facial hair. Another option which may be more appealing to some mine workers than a half-mask respirator is an airstream helmet, which provides filtered air in the breathing zone of the worker. The airstream helmet does not restrict breathing, provides some cooling, and does not require the worker to be clean shaven to work properly. These helmets are being used to help reduce respirable dust exposures in some coal mines, and this study investigated how effective this helmet may be for reducing DPM exposures. The airstream helmet with a HEPA filter was found to reduce DPM exposures by over 99% in static conditions by both mass and particle counting data. The airstream helmet can be an important part of a mine’s DPM control plan because it can provide clean air into a mine worker’s breathing zone in areas of elevated concentrations.

Mining vehicle manufacturers are developing lithium-ion (Li-ion) battery electric vehicles as an alternative to diesel-powered vehicles. In gassy underground mines, explosion-proof (XP) enclosures are commonly used to enclose electrical ignition sources to prevent propagation of an internal methane (CH4) air explosion to a surrounding explosive atmosphere. Li-ion batteries can create pressurized explosions within sealed enclosures due to thermal runaway (TR). Researchers at the National Institute for Occupational Safety and Health (NIOSH) measured TR pressures of lithium iron phosphate (LFP) cells as a function of free space within sealed enclosures and observed an inverse power relationship. A well-confined cell produced 294 bar (4260 psia) of pressure during a TR, far exceeding minimum pressure containment specifications for conventional XP enclosures. Results indicate that adding enough free space surrounding LFP cells can reduce TR pressures to levels below that expected for CH4-air ignitions. Measured TR temperatures were below the minimum autoignition temperature of CH4-air.

This paper presents the results of large-scale fire experiments on evaluating the performances of carbon monoxide (CO) and smoke sensors at low ventilation velocities. Experiments using three different combustibles—conveyor belt, coal, and diesel fuel—were conducted in the Experimental Mine at the National Institute for Occupational Safety and Health (NIOSH) Bruceton Research Facility. A total of eight sensor stations were located downstream of the fire with each station containing CO, smoke, carbon dioxide, oxygen, humidity, barometric pressure, temperature sensors, and two airflow sensors. The airflow velocity ranged from 0.22 to 0.26 m/s (44 to 51 fpm) in the tests. The response times were recorded for the CO and smoke sensors at each sensor station when smoke and gaseous products of combustion of each burning combustible reached the station. The response times of the CO sensors were used to determine the appropriate sensor spacing in the belt entry with a low air velocity. The performance of the smoke sensor was found to be affected by the high humidity in the experiments. The results on proper selection of sensors and the determination of sensor spacing at a low ventilation velocity can be helpful for ensuring sufficient early fire warning for underground workers, thereby improving the health and safety of miners.

BACKGROUND: During 2010-2017, rates of reported chlamydia decreased among young Black women but increased for White women and all men. Since chlamydia case rates can be influenced by changes in prevalence, screening, and other factors, we compared chlamydia prevalence trends in a sentinel population to national case rate trends to understand potential drivers of case rate trends. METHODS: Chlamydia prevalence was calculated annually among 16-24 year old entrants to the National Job Training Program (NJTP) during 2010-2017. An expectation-maximization-based maximum likelihood approach was used to adjust for misclassification due to imperfect test sensitivity and specificity. Models were stratified by sex, age, and race/ethnicity. A statistically significant trend in prevalence was defined as non-overlapping 95% confidence intervals comparing 2010 and 2017. Trends in chlamydia prevalence were compared to trends in case rates using percentage change over time; relative changes ≥10% were considered meaningful. RESULTS: Among NJTP entrants during 2010-2017, chlamydia prevalence was stable for all Black women, while case rates decreased for adolescents (-12%) and were stable for 20-24 year-olds (-4%). Among adolescent White women, prevalence was stable while case rates increased (+30%). For White women aged 20-24 years, prevalence increased +62% and case rates increased +43%. Trends in prevalence differed from trends in case rates for all subgroups of men. CONCLUSIONS: Prevalence trends in this sentinel population differed from national case rate trends for Black women, White women, and men, suggesting potential decreased screening among Black women 16-19, increased prevalence among White women 20-24, and increased screening among men.

BACKGROUND: Reducing transmission depends on the percentage of infected partners treated; if many are missed, impact on transmission will be low. Traditional partner services metrics evaluate the number of partners found and treated. We estimated the proportion of partners of syphilis patients not locatable for intervention. METHODS: We reviewed records of early syphilis cases (primary, secondary, early latent) reported during 2015-2017 in seven jurisdictions (Florida, Louisiana, Michigan, North Carolina, Virginia, New York City, and San Francisco). Among interviewed syphilis patients, we determined the proportion who reported named partners (with locating information), reported unnamed partners (no locating information), and did not report partners. For patients with no reported partners, we estimated their range of unreported partners to be between one and the average number of partners for patients who reported partners. RESULTS: Among 29,719 syphilis patients, 23,613 (80%) were interviewed and 18,581 (63%) reported 84,224 sex partners (average=4.5; 20,853 (25%) named and 63,371 (75%) unnamed). An estimated 11,138 to 54,521 partners were unreported. Thus, 74,509 to 117,892 (of 95,362 to 138,745) partners were not reached by partner services (78-85%). Among interviewed patients, 71% reported ≥1 unnamed partner or reported no partners; this proportion was higher for men who reported sex with men [MSM] (75%), compared to men who reported sex with women only (65%), and women (44%). CONCLUSION: Approximately 80% of sex partners were either unnamed or unreported. Partner services may be less successful at interrupting transmission in MSM networks where a higher proportion of partners are unnamed or unreported.

We conducted a survey among women attending an urban public sexually transmitted disease clinic to determine type and frequency of intravaginal cleansing practices. Both intravaginal washing and douching were frequent, performed mostly for routine hygiene, and associated with self-report of STI and bacterial vaginosis (douching) and bacterial vaginosis (intravaginal washing).

Continuous monitoring of carbon monoxide and other fire-related parameters by means of an atmospheric monitoring system (AMS) has been used by the mining industry for early fire detection in underground mines. The National Institute for Occupational Safety and Health (NIOSH) initiated a project to integrate real-time AMS sensor data with NIOSH’s mine fire simulation program, MFIRE 3.0, to simulate and predict the spread of smoke that would provide assistance to mine fire emergency response personnel. Determining the heat release rate of a fire using the monitored sensor data was a critical component of the successful completion of this project. NIOSH researchers developed a direct method to calculate the heat release rate when a fire is within close range of sensors. However, this method is only applicable to the case where a fire occurs in AMS-monitored airways. This paper presents an improved method for determining the fire heat release rate for complicated scenarios where a fire is distant from sensors and airflow splits and merges are present. The method was validated using a full-scale diesel fuel fire test conducted in the Safety Research Coal Mine at the Pittsburgh Mining Research Division and can help mine operators and safety personnel make informed decisions during a fire emergency.

Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted a study in an isolated zone of an underground mine to characterize aerosols generated by: (1) a diesel-powered personnel carrier vehicle operated over a simulated light-duty cycle and (2) the simulated repair of existing equipment using manual metal arc welding (MMAW). Both the diesel-powered vehicle and MMAW process contributed to concentrations of nano and ultrafine aerosols in the mine air. The welding process also contributed to aerosols with electrical mobility and aerodynamic mobility count median diameters of approximately 140 and 480 nm, respectively. The welding particles collected on the filters contained carbon, iron, manganese, calcium, and aluminum.

Diesel particulate matter (DPM) produced from vehicle and equipment diesel exhaust (DE) is a common industrial inhalation hazard, particularly in underground mines. The sub-micron particles of DPM (&lt; 800 nm) are composed of a carbonaceous core operationally defined as elemental carbon (EC), which are irregularly arranged graphitic- like &quot;spherule&quot; structures, and a wide-variety of adsorbed, semivolatile organic carbon compounds (OC). In addition to associating chronic exposure to DPM with immunological, respiratory and cardiovascular health issues, the International Agency for Research on Cancer (IARC) categorizes this material as carcinogenic to humans, with workers regularly exposed to it demonstrating an elevated risk for lung cancer. Given the long-term health risks associated with repeated and prolonged exposure to DPM, efforts are being directed at reducing the exposure of miners and other workers who may encounter high levels of DPM over the course of a typical working day.

NIOSH researchers designed a high-sensitivity (HS) cassette to improve the limit of detection of the National Institute for Occupational Safety and Health's (NIOSH) method 5040 and the Airtec near real-time diesel particulate matter (DPM) monitor. This was achieved by reducing the size of the diesel particulate matter deposition spot from 8.0 cm(2) (NIOSH method 5040 mining samples) and 7.6 cm(2) (Airtec samples) to 0.5 cm(2). When compared with the standard cassette, the new high-sensitivity cassette improves the limit of detection of NIOSH method 5040 by approximately five times, and the differences between the elemental carbon results from the HS cassette and the standard three-piece cassette were within statistical error. The limit of detection for Airtec measurements improved by approximately 15 times, and the elemental carbon results with the HS cassette between the Airtec and NIOSH method 5040 were within statistical agreement. When used in the Airtec monitor, the high-sensitivity cassette showed promise for measuring short-duration spot checks of ambient concentrations but was limited when performing some long-term sampling due to the resultant loss of dynamic range. Only up to 7 mug of elemental carbon was collected onto the HS cassette before the increase in pump backpressure caused the flow fluctuations to exceed targeted values by unacceptable levels. The HS cassette shows promise for effective engineering evaluations of control technologies and strategies and near real-time diesel particulate matter measurements for a variety of occupations.

A study was conducted in an underground mine with the objective to identify, characterize, and source apportion airborne aerosols at the setup face and recovery room during longwall move operations. The focus was on contributions of diesel- and battery-powered heavy-duty vehicles used to transfer equipment between the depleted and new longwall panels and diesel-powered light-duty vehicles used to transport personnel and materials to various locations within the mine. Aerosols at the setup face were found to be distributed among diesel combustion-generated submicrometer and mechanically generated coarse aerosols. According to the data, the submicrometer aerosols downstream of the setup face were sourced to diesel exhaust emitted by vehicles operated inside and outside of the panel. Depending on the intensity of the activities on the panel, the outby sources contributed between 12.5 and 99.6% to the average elemental carbon mass flow at the setup face and recovery room. Extensively used light-duty vehicles contributed measurably to the elemental carbon concentrations at the setup face. The number concentrations of aerosols downstream of the setup face were associated with aerosols generated by combustion in diesel engines operated in the shield haulage loop and/or outside of the longwall panels. Entrainment of road dust by diesel or battery-powered load-haul-dump vehicles operated near the measurement site appears to be the primary source of mass concentrations of aerosols. The findings of this study should help the underground mining industry in its efforts to reduce exposures of miners to diesel and coarse aerosols.