Characterizing and Communicating Past, Present and Future Risk

PO103 
Characterizing and Communicating Past, Present and Future Risk 

Monday, June 1, 2015, 10:30 AM - 12:30 PM​​​

CS-103-01 Characterizing Risk at an Industrial Site from Leaking Underground Storage Tanks Containing Diesel Fuel

J. Persky, ENVIRON International Corp., Chicago, IL; F. Boelter, ENVIRON International Corp., Chicago, IL; S. Song, ENVIRON International Corp., Chicago, IL; B. Schnorr, ENVIRON International Corp., Chicago, IL

Situation/Problem: In a newly industrialized country, an activist filed a complaint with the local agency alleging that a facility is “a living source of contamination and that the workers received, during their workday, emissions of toxic gases coming from the subsoil.” This complaint was based on publically available reports related to site investigation and remediation work. The reports contained relevant technical errors and characterized risk using an approach which was inherently improper. We revisited the basis of the risk assessment which precipitated misunderstanding, anxiety, and outrage in the community and workforce.

Resolution: A review of the RA and air sampling data inside the subject building indicated there is no significant risk to workers. The predicted indoor air concentrations were unrealistically high due to mathematical errors and compounded by the use of conservative assumptions to develop site remediation objectives. Revision of the RA models using realistic parameters demonstrated that theoretical risk did not exceed the regulatory risk criteria. Actual air sampling data confirmed the unfounded risk characterization regarding indoor air concentrations of petroleum hydrocarbons in the building.

Results: The RA review noted a number of conservative assumptions or incorrect model inputs. Corrections included 1) the use of Raoult’s law, 2) actual floor slab thickness, 3) lack of visible cracks in the floor slab, 4) air change rates, and 5) employee occupancy durations <<8-hours/day. The results still represented a conservative scenario but showed that the predicted maximum indoor air concentrations were at least two to three orders of magnitude lower than those predicted in the original RA. The cumulative cancer risk for a hypothetical workday with lifetime exposure to the predicted maximum indoor air concentrations was 2x10-9.

Lessons Learned: A well-intentioned but flawed risk characterization can create problems where none actually exist. It is critical to understand the context within which a RA is prepared and to scrutinize the basis of the assumptions when looking to apply the risk findings to alternative objectives. RAs which are developed using hypothetical scenarios to guide site remediation efforts are fundamentally different than RAs purposed to evaluate actual risk to workers. Conservative and unrealistic estimations of G, Q, and t can lead to exaggerated and unrealistic estimates of exposure or dose.


CS-103-02 A Qualitative Approach for Determining the Likelihood of PCBs in Manufactured Products aboard Maritime Vessels

M. Plisko, Environmental Profiles, Inc., Columbia, MD; J. Spencer, Environmental Profiles, Inc., Columbia, MD; P. Fabian, Environmental Profiles, Inc., Columbia, MD

Situation/Problem: Prior to 1980, some products used in the shipbuilding industry contained polychlorinated biphenyls (PCBs) and were installed as shipboard components during new vessel construction. The manufacture and use of PCBs in the US was prohibited in 1979, however the US EPA has suggested that products containing PCBs could have been accidently installed aboard vessels constructed at US shipyards from 1980 to 1984. Many vessels constructed during this time are nearing or have already surpassed their expected service lives, and will likely be sold for recycling or repurposing. According to EPA, vessels with manufactured items containing ≥50 ppm PCBs are prohibited from being sold for export to other nations, whether intended for recycling or repurposing. Since many of these vessels are operational and seaworthy, destructive sampling to determine the presence of PCBs cannot be performed.

Resolution: An investigative process was developed to determine the likelihood of whether manufactured items containing PCBs were either originally installed or presently remain on board cargo vessels constructed at US shipyards prior to and after 1979. The process consisted of four components including document and records review; complete visual inspection of the entire vessel; interviews of persons having specialized knowledge regarding the vessel’s design, construction and operation; and a search of available regulatory information.

Results: The process was used to evaluate seven vessels built between 1975 and 1987. The results of the investigation revealed the presence of PCB-containing fluorescent lighting ballasts in three of the four older vessels (1975, 1978, and 1979) and potential for the presence of PCB-containing electrical cable in the oldest vessel (1975). There was no indication of manufactured items containing regulated concentrations of PCBs aboard the three newer vessels (1984, 1984, and 1987). The use of this procedure in each case satisfied the US EPA due diligence requirement for evaluating the presence of PCBs aboard vessels being offered for export.

Lessons Learned: The lessons learned from the use of this procedure revealed that many products used in maritime construction that historically may have contained PCBs were not present due to regular overhaul, normal product replacement, and modernizations performed over the 25+ year lifecycles of the inspected vessels.


CS-103-03 Communicating Exposure and Risk Concepts Regarding Railroad Maintenance and Repair Workers

F. Boelter, ENVIRON International Corp., Chicago, IL; J. Persky, ENVIRON International Corp., Chicago, IL; D. Podraza, ENVIRON International Corp., Chicago, IL; W. Bullock, CSX Transportation, Jacksonville, FL

Situation/Problem: Whether there is big data or small data, a challenging area for professionals is to determine how to effectively characterize the risk presented by the exposure and to convey this characterization in a way that has meaning to the stakeholder. For a particular set of past practice data, four broad groups of railroad stakeholders were identified as recipients of the risk characterization: 1) historical railroad workers, 2) current railroad workers, 3) railroad management, and 4) exposure science professionals.

Resolution: Airborne asbestos exposures related to railroad maintenance and repair past practices was studied since no corresponding objective data was found in the published literature. Three scenarios were developed regarding the removal and handling of asbestos woven tape, historically used to lag pipes during the steam era as well as the diesel-electric era. A challenge arose regarding how best to fairly and effectively present the data and results given that the four broad groups of stakeholders had potentially different interests, different technical skills, and different ways of learning and processing information. Alternative ways of communicating the study results needed to be developed.

Results: Sampling results over three days demonstrated the six 8-hr TWAs as well as the seventy-two 30-min task based ELs were less than the respective current OSHA PEL of 0.1 f/cc and 1 f/cc. The data was compiled, analyzed, and presentation options were prepared by numerical descriptive statistics, box and whisker charts, Bayesian Decision Analysis charts, hazard banding charts, and SAE/variance vs. PEL graphs. Each of the presentation alternatives had their own merits and ease of being understood by the four broad groups of stakeholders.

Lessons Learned: An exposure assessment in support of a risk characterization needs to consider weight of evidence, a systematic review, analogies to existing data, implications of missing data, uncertainty, and transparency. No single method is the “best” method for presenting study data. The professional preparing a risk characterization needs to communicate risk concepts using a variety of tools such that the stakeholder understands the information and can make their own informed decisions. Policy needs to be based on evidence and not philosophy, science needs to be distilled and translated, and the message needs to be understandable and not watered down.


SR-103-04 Russian Anthophyllite: Chemical Composition and Mesothelioma Potency Estimate

A. Korchevskiy, J. Rasmuson, E. Rasmuson, Chemistry & Industrial Hygiene, Inc., Wheat Ridge, CO; M. Sanchez, RJLee Group, Inc., Monroeville, PA

Objective: To characterize the mineral composition of a fibrous amphibole that was mined in the Russian region of Ekaterinburg and to estimate the potential pleural mesothelioma potency factor range for this mineral. 

Methods: A suspect amphibole asbestiform specimen was obtained in the Russian Federation where the mineral is on public display in a local park. Characterization of this specimen was accomplished using Transmission Electron Microscopy (TEM) employing select area electron diffraction and zone axis indexing, Mössbauer spectroscopy to determine the FeO to Fe2O3 ratio and electron probe micro-analysis (EPMA) for major elemental composition. Empirical modeling (Korchevskiy, Rasmuson, Rasmuson, 2014) based on chemical composition and lung biopersistence to determine a mesothelioma potency factor was accomplished. The general range of the determined potency was compared with implications from the literature, as well as an RM value range from the epidemiological information from the Ekaterinburg region in Russia. 

Results: The amphibole composition was determined to be asbestiform anthophyllite and based on morphology and chemical analysis, with average composition of 58% SiO2, 27% MgO, 2.3% Fe2O3, and 8% FeO. If the average half-life in the lung of the material is assumed to be 240 months (as for amosite), application of the empirical model yields an average mesothelioma potency of RM = 0.013 %/f/cc-year (95% CI 0.005, 0.029). Available data for mesothelioma incidence in the community neighboring the mine suggests a slightly higher potency of 0.041 (95% CI 0.006-0.1), but there is no statistically significant difference between the estimates (P=0.77). 

Conclusions: Russian mining of anthophyllite asbestos was not well recognized as occupational and environmental hazards. In spite of the apparent closure of anthophyllite mining operations, its effect on mesothelioma mortality in the country should not be ignored. Moreover, scant data exists on anthophyllite potency factors. Utilization of the proposed empirical model (depending on chemical composition of fibers and lung half-life) yields acceptable results if compared to levels determined from epidemiological studies. 


CS-103-05 Modeling Work Effectiveness of Firefighters with Varying Shift Schedules

S. Williams, V. McDonough, L. Racz, U.S. Air Force, Apo, AE

Situation/Problem: The work effectiveness of firefighters and other shift workers has long been recognized as vulnerable to degradation with night and rotating schedules. Cognitive performance depends on an individual’s combined circadian and homeostatic processes. Those who work during other shifts and sleep during the day disrupt the balance between the homeostatic and circadian processes. These effects can have serious consequences among emergency workers such as firefighters with slowed reaction time, reduced ability to make decisions, and loss of situational awareness. Despite the risks, individuals tend to inaccurately assess the magnitude of their own vulnerability to fatigue. One approach to mitigating these effects is development and use of a Fatigue Risk Management System (FRMS). Since such a system is science based and data driven, the use of a model can help to predict performance as a function of sleep attained. One of these models, the Sleep, Activity, Fatigue and Task Effectiveness model, provides the algorithm used in the Fatigue Avoidance Scheduling Tool (FAST).

Resolution: For 14 days, a total of 34 firefighters were given an anonymous sleep survey. These firefighters included those from two different 24-hr shift teams as well as those from conventional eight-hour shifts. They were asked to document their perceived quality of sleep as well as hours worked, any abnormalities with sleep, naps taken, and circadian rhythm synchrony. The data was then input into FAST which predicted the percentage effectiveness for each participant.

Results: The data depicted an exponential decrease in effectiveness as the work week progressed. The benefit of strategic naps was reinforced by one of the 24-hr teams, where half of the team consistently napped. When personnel listed their perceived circadian rhythm peaks and troughs, most workers had a circadian rhythm synchrony. Extended hours on a regular basis impacted the homeostatic balance. This analysis gave leadership their first opportunity to see a subjective topic (fatigue) in an objective fashion.

Lessons Learned: Identification of individuals at most risk for fatigue based errors is still subjective in nature and requires both a qualitative and quantitative approach to identifying appropriate fatigue countermeasures for certain military career fields. The use of a fatigue model can be an effective component in a FRMS in order to help manage sleep and work schedules effectively and improve work performance and safety.


CS-103-06 Six Sigma Approach to Improving your Office Ergonomics Process

T. Silva, Atlas Ergonomics, Grand Haven, MI

Situation/Problem: Many organizations have been running an office ergonomics process for several years and have plateaued in performance. They do not know, with any level of confidence, what part of the process should be improved and to what level.

Resolution: This presentation will look at two case studies and how each company utilized Six Sigma methodologies to improve their office ergonomics process: Case Study #1 – One of the nations’ largest financial institutions. Their process encompasses coverage of greater than 180,000 employees deployed over 5,500 individual locations across the country. Case Study #2 – One of the world’s largest, multinational professional services networks with a large percentage of the work population using hoteling stations and working remotely from client and home office locations.

Results: The process provides a data driven approach to better measure program performance. It is a more standardized approach to evaluating and controlling ergonomic hazards, and offers significant reductions in errors in the office ergonomics process..

Lessons Learned: Learn when and how to use different Six Sigma methods to collect Voice of the Customer and determine Critical to Quality characteristics. Use process flow diagrams to document the flow of information in your office ergonomics process. Analyze root cause with Fishbone diagrams, brainstorm to develop process improvements and use FMEAs to prioritize improvements. Trial and test improvements in a Design of Experiment format before rolling out corporate wide.