Sustainability and Safety: A Prevention through Design (PtD) Success Story

Prevention through Design (PtD) addresses occupational safety and health (OSH) needs in the design and redesign phases to prevent or reduce the work-related risks to ‘As Low As Reasonably Practicable’ (ALARP). PtD concepts and methodologies have been successfully applied by various industries to specific projects involving different phases of a system’s design, construction, installation, operation, maintenance, repair, and end-of-use for the purpose of avoiding and reducing OSH risks. In addition, PtD concepts can be applied to such projects for the purpose of improving productivity, efficiency, and sustainability.

The first PtD standard was published in 2011 with the primary goal to help educate designers; engineers; machinery and equipment manufacturers; environmental, health, and safety (EHS) professionals; business leaders; and workers in understanding and implementing PtD methods in the design and re-design of workplace facilities, processes, equipment, tools, methods, and even sustainability initiatives.

EHS professionals face challenges in persuading management that safety and sustainability efforts can greatly benefit the organization in achieving business objectives. To be successful, EHS professionals must become change agents and help management transform safety and sustainability into an accepted business value for the organization. This requires EHS students and professionals to understand PtD principles and help integrate them into standard business and sustainability practices.

A major barrier to the adoption of PtD sustainability initiatives is the perception that the cost/benefit ratio of such projects is unfavorable. EHS professionals should recognize business cost drivers and justify PtD expenditures in the early stages of sustainability projects, green buildings, and product development. The authors have developed a PtD model that can help EHS professionals make the business case for PtD sustainability projects. The PtD model incorporates risk assessment, hierarchy of risk treatment (HoRT), productivity, sustainability, financial analysis, and future state projections. This model addresses the current Board of Certified Safety Professionals’ (BCSP) Associate Safety Professional (ASP) and Certified Safety Professional (CSP) examination domain changes, which include:

ASP (BCSP, 2025a):

Domain 1.  Calculate financial indicators (e.g., cost-benefit analysis, cost of risk, life cycle cost, return on investment, effects of losses)

Domain 2. Apply appropriate hazard and risk analysis methods (e.g., hazard analysis, fishbone, change analysis)

Domain 3. Ergonomics

Domain 7. Environmental management

CSP (BCSP, 2025b):

Domain 1. Describe the principles of minimizing hazards using Prevention-Through-Design

Domain 2. Describe the Management of Change process (prior, during, after);

Recognize safety, health, and environmental management and audit systems (e.g., ISO 14000 series, 45001, 19011, ANSI Z10);

Describe system safety analysis techniques (Safety Case approach, risk summation)

Apply budgeting, finance, and economic analysis techniques and principles (e.g., timelines, budget development, resourcing, return on investment, cost/benefit analysis, role in procurement process)

Domain 3. Risk Management

Domain 5. Environmental Management

To demonstrate the applicability of the model and provide practical examples of BCSP’s ASP/CSP domains application, the authors would like to present a case study that was suitable for practical demonstration and for use as a best practice model. A sustainability project for refuse truck improvements will be discussed in this paper. In the model, PtD principles were combined with recently developed risk assessment tools, productivity improvements, and environmental and sustainability initiatives. This case study demonstrates how EHS professionals can play a significant role in the development of new sustainability projects, business plans, and the implementation of Lean Six Sigma (LSS) practices, designed to reduce the risk of injuries and illnesses and improve productivity.

1.1 Research Question

This paper focuses on developing a new decision-making model to study whether PtD methods are applicable in environmental, safety, and sustainability improvement projects.

1.2 History of PtD

Prevention through Design is not a new concept and, as with many worthwhile endeavors, has roots in the work of several previous individuals and organizations (Manuele, 2007; ANSI/ASSP, 2021). The work of Edward Deming via his total quality management (TQM) process certainly provided foundational underpinnings for PtD (Manuele, 2008; Deming, 1982). Deming gives credit to others for the TQM process, and thus the circle continues to turn and involve many participants. The American Society of Safety Professionals (ASSP) published a position paper on Designing for Safety in the 1990s (ASSE, 1994). The National Institute for Occupational Safety and Health (NIOSH) gave the PtD movement a boost via a variety of meetings and publications, starting in the 1990s. In late 2010, NIOSH released its PtD plan (NIOSH, 2010). ASSP and the American Industrial Hygiene Association (AIHA) have also provided significant support for PtD. ASSP is the Secretariat for the first version of the standard and the updated ANSI/ASSP version of the PtD standard.

PtD has been gaining momentum for the past several years, as evidenced by its inclusion in current occupational safety and health textbooks (Blunt, et al., 2011; Lyon and Popov, 2020). The authors believe this trend will continue for the foreseeable future, as Fred Manuele’s publications indicate (Manuele, 2008a; Manuele, 2008b).

 

Trash collection requires a significant number of repetitive manual material handling movements by workers, resulting in musculoskeletal disorders (MSDs), including lower back and carpal tunnel syndrome (CTS) injuries. For the organization in the study, the additive effect of these safety risks was recognized as a main concern for its business continuity and sustainability goals. Human Resources (HR) reported difficulties in hiring new employees, and the organization experienced a high turnover rate. As a result, management needed to take steps to reduce MSDs risks and improve productivity.

This research project demonstrates potential savings an organization can realize from the implementation of PtD and sustainability initiatives. The organization formed a risk reduction team to help prepare a business case for improvement. The team identified priorities and developed a project model. The purchase of new mechanized refuse trucks had to be justified. PtD and sustainability goals were identified as a key component of the project. The main requirement was that the new refuse trucks were to be designed in a way to eliminate or significantly reduce MSDs risks.

The recommendation was to utilize PtD, risk management, and LSS tools to perform a current state-of-the-art risk assessment and develop intervention priorities. PtD and risk reduction tools were utilized to develop future-state risk estimations and projections. Productivity gains were evaluated utilizing common LEAN tools, and project cycle efficiency (PCE) was calculated for current state productivity and future state projections. A modified fishbone diagram was then used to evaluate the current state vs. the future state process.

To analyze and evaluate potential solutions for this project, the authors developed a Microsoft Excel-based business analysis tool. The tool was used to evaluate a number of business-related factors, including total annual incidence cost before the intervention and total annual incidence cost after the intervention, and to calculate incident benefit and cost savings. The team performed an estimated return on investment (ROI) by adding net savings, new revenue (generated from increased productivity), and other savings on maintenance, fuel, insurance, etc. The estimated ROI was displayed as a numerical value as well as a percentage. The team also estimated the net present value (NPV) and the payback period for the safety investment. Note: Internal rate of return (IRR) is another business term and is usually considered a simplified alternative to NPV. The tool calculates and displays IRR as a percentage.

Recognizing that business managers prefer to see comparisons of several proposals rather than a single solution, a worksheet was developed and presented to compare four different proposals. The NPVs for the different proposals were compared and displayed as numerical values, while IRR and ROI for all proposals/solutions were displayed as percentages. To satisfy expectations and gain support for EHS improvements, the team conducted a cost-benefit analysis to assess potential risk reductions. Based on the initial analysis, it was decided to move forward with new mechanized compressed natural gas (CNG) refuse trucks.

The business analysis revealed a payback period of a little more than four years with an IRR of 12%. The organization’s management requested that non-financial benefits be included in the model for a comprehensive evaluation. The organization requested assistance from an EHS consulting team to evaluate the emissions of its existing diesel trucks and compare them to those of the new CNG trucks from a sustainability perspective. Particulate matter (PM 10), NO2, and CO levels were evaluated. In addition, volatile organic compound (VOC) levels were also compared. The air was tested for VOCs utilizing a photoionization detector (PID). The sampling was performed utilizing a PID with an ionization potential (IP) for the UV lamp of 10.6 eV. The air quality pollutants were measured near the side platform (step) where the refuse collector steps on and holds onto the handle. These measurements were considered as air quality screening only.

1.3 Research Project Description

Trash collection requires a significant number of repetitive manual material handling movements by workers, resulting in musculoskeletal disorders (MSDs), including lower back and carpal tunnel syndrome (CTS) injuries. For the organization in the study, the additive effect of these safety risks was recognized as a main concern for its business continuity and sustainability goals. Human Resources (HR) reported difficulties in hiring new employees, and the organization experienced a high turnover rate. As a result, management needed to take steps to reduce MSDs risks and improve productivity.

This research project demonstrates potential savings an organization can realize from the implementation of PtD and sustainability initiatives. The organization formed a risk reduction team to help prepare a business case for improvement. The team identified priorities and developed a project model. The purchase of new mechanized refuse trucks had to be justified. PtD and sustainability goals were identified as a key component of the project. The main requirement was that the new refuse trucks were to be designed in a way to eliminate or significantly reduce MSDs risks.

The recommendation was to utilize PtD, risk management, and LSS tools to perform a current state-of-the-art risk assessment and develop intervention priorities. PtD and risk reduction tools were utilized to develop future-state risk estimations and projections. Productivity gains were evaluated utilizing common LEAN tools, and project cycle efficiency (PCE) was calculated for current state productivity and future state projections. A modified fishbone diagram was then used to evaluate the current state vs. the future state process.

To analyze and evaluate potential solutions for this project, the authors developed a Microsoft Excel-based business analysis tool. The tool was used to evaluate a number of business-related factors, including total annual incidence cost before the intervention and total annual incidence cost after the intervention, and to calculate incident benefit and cost savings. The team performed an estimated return on investment (ROI) by adding net savings, new revenue (generated from increased productivity), and other savings on maintenance, fuel, insurance, etc. The estimated ROI was displayed as a numerical value as well as a percentage. The team also estimated the net present value (NPV) and the payback period for the safety investment. Note: Internal rate of return (IRR) is another business term and is usually considered a simplified alternative to NPV. The tool calculates and displays IRR as a percentage.

Recognizing that business managers prefer to see comparisons of several proposals rather than a single solution, a worksheet was developed and presented to compare four different proposals. The NPVs for the different proposals were compared and displayed as numerical values, while IRR and ROI for all proposals/solutions were displayed as percentages. To satisfy expectations and gain support for EHS improvements, the team conducted a cost-benefit analysis to assess potential risk reductions. Based on the initial analysis, it was decided to move forward with new mechanized compressed natural gas (CNG) refuse trucks.

The business analysis revealed a payback period of a little more than four years with an IRR of 12%. The organization’s management requested that non-financial benefits be included in the model for a comprehensive evaluation. The organization requested assistance from an EHS consulting team to evaluate the emissions of its existing diesel trucks and compare them to those of the new CNG trucks from a sustainability perspective. Particulate matter (PM 10), NO2, and CO levels were evaluated. In addition, volatile organic compound (VOC) levels were also compared. The air was tested for VOCs utilizing a photoionization detector (PID). The sampling was performed utilizing a PID with an ionization potential (IP) for the UV lamp of 10.6 eV. The air quality pollutants were measured near the side platform (step) where the refuse collector steps on and holds onto the handle. These measurements were considered as air quality screening only.

Considering the projected safety improvements (reduction of MSDs exposures), gains in productivity and non-financial benefits, and reduced air pollutant emissions, management made the decision to invest in the new CNG truck fleet.

A new PtD and business analysis decision-making model was used to evaluate improvements to the refuse collection process. This research identified potential areas for EHS professionals to consider the business aspect in the evaluation and decision-making process. The new PtD model developed by the authors incorporates risk assessment, HoRT, productivity, financial analysis, and future state projections. The model follows Define, Measure, Analyze, Improve, and Control (DMAIC) logic. Separate tools were developed for each phase. For instance, Delphi, brainstorming, and preliminary risk assessment (PRA) were used in the “Define” phase. A semi-quantitative risk assessment matrix (RAM) was used in the “Measure” phase to prioritize the risks and modify the procedure to estimate risk reduction after the proposed EHS intervention. A striped bowtie risk assessment method was used to estimate total risk or risk summation (CSP 11, Domain 2). Several other tools were utilized during this evaluation, including value stream mapping (VSM), PCE, and the Pareto 80/20 analysis. Next, adjustments were made, and the improvements were evaluated utilizing Lean Six Sigma tools.

Air pollutant levels were evaluated for the current diesel trucks and compared to the new CNG trucks. The emissions were evaluated utilizing direct reading instruments.

The authors present the following case study to demonstrate the applicability of the newly developed PtD and sustainability model. For confidentiality purposes, the team members and company name have been removed.

2.1 Case Study

Refuse collection companies that still operate manual trash collection services typically have a very high MSD rate. This can lead to a high turnover rate, a high absenteeism rate, and significant financial losses for the company. Therefore, a risk-based business plan for replacing old refuse trucks with new mechanized trucks was needed.

To begin, an ergonomics risk assessment was completed utilizing the PtD risk assessment tools. High-priority areas for improvements were identified and evaluated. The study included an initial cost-benefit analysis, and gross cost savings from EHS interventions were calculated. NPV, payback period, simple ROI, and IRR calculations from EHS interventions were also included in the study.

The main purpose of the project was to demonstrate the benefits of mechanized refuse collection trucks compared to conventional refuse collection trucks currently in use (Exhibit 1).

Exhibit 1

Refuse Collection Trucks

Conventional refuse collection truck

Mechanized refuse collection trucks

Simple digital images were used to understand the process and develop a possible intervention plan. However, the authors had to develop a comprehensive management plan that would lead to a complete analysis of the process and convince the management of the benefits of investing in new trucks. The team members observed the process and recorded the time required for each step. The steps are presented below:

Step 1. Position the refuse truck.

Step 2. Lift two polyethylene bags.

Step 3. Lift and dump the bags.

Step 4. Repeat steps 2 and 3, lifting and dumping two more bags. Four polyethylene (poly) bags are allowed per household.

Step 5. Compress/compact the trash.

Step 6. Refuse collector steps on the side platform (step) and holds on to the handle.

Step 7. Drive to the next house.

An initial risk assessment was performed to assess and estimate the safety risks and the potential injuries. After several meetings with the company’s risk management and accounting professionals, the team developed a worksheet with risk estimation options. Risk was estimated based on a 5×5 risk assessment matrix (RAM), presented in Fig. 1. The formula selected to estimate risk level was a simple multiplication of Severity x Likelihood, resulting in a risk level between 1 and 25. The risk results were color-coded for better visualization.

Figure 1

5×5 Risk Assessment Matrix

Next, the preliminary risk assessment worksheet was completed to individually assess the risks. The risk assessment worksheet used was based on the well-established risk pathway model (ASSP TR 2020) and is presented in Fig. 2.

Figure 2

Current State Risk Assessment Worksheet

The PRA method shown in Fig. 2 is a linear method that was used to individually assess each risk. The PRA model is commonly used for risk prioritization. Based on the presented current state risk assessment, it was clear that back strain exposure was the highest risk for this operation. Note that to consider the additive effects of the individual risks, the risk summation method, as stated in BCSP’s CSP Domain 2, was used to assess the total risk level. For example, heat stress can increase the risk of MSDs for workers performing repetitive manual material handling, like refuse collectors. The additive effects of physical exertion in hot conditions can lead to fatigue, decreased dexterity, and impaired judgment, increasing the risk of injuries such as strains, sprains, and other MSDs (NIOSH, 2024). In addition, the severity of the additive effects of such exposures may lead to hospitalizations or even fatal outcomes.

To address some of the shortcomings of the linear risk assessment model, the authors developed the striped bowtie model (Lyon and Popov, 2017), as depicted in Fig. 3.

Figure 3

Striped Bowtie Model for Refuse Collectors’ Risks

The total risk or risk summation level, as shown in Fig. 3, was estimated at 12, compared to individual risks of 9, 6, and 6, respectively. This risk summation estimation is based on the fact that the additive effects of extreme temperatures may likely increase the risk of MSDs. Also, the total risk was reduced by only 10% because the only preventive measures in place were administrative controls.

A Pareto chart was prepared to visualize the highest cost of injuries and illnesses. Not surprisingly, MSDs were at the top of the chart for safety-related costs of injuries and illnesses. The financial expenses were clearly communicated to the risk manager, and it became obvious that the costs of injuries and illnesses were unsustainable. The next task was to collect data and prepare a cost-benefit analysis, as shown in Fig. 4.

 

Figure 4

Cost-Benefit Analysis Worksheet

The worksheet was developed specifically for this project; however, the format can be used for other projects. The form is an analysis of different categories and the financial impact of each category. Some categories were easily quantifiable, such as workers’ compensation cost, annual salaries and benefits obtained from the accounting department, and fuel and maintenance costs obtained from the maintenance department. Unfortunately, the company’s experience modification rating (EMR) for worker compensation claims was not shared with the team. EMR is the objective measurement of each employer’s claims experience. The published manual rate for each state is multiplied by the employer’s EMR to determine the premium rate paid by the employer. An EMR below 1.00 indicates that the employer will pay premiums below the manual rate. The organization was approaching an EMR of 1.00, and it was vitally important to lower the rate to avoid increased insurance premiums. Due to confidentiality concerns, the impact of EMR was not disclosed and could not be included in the calculations. The organization did not disclose the cost of hiring new employees. Therefore, it was not included in the calculations.

EHS professionals are well aware that obtaining all financial variables is not an easy task. Therefore, many what-if scenarios have to be prepared, and such scenario analyses are not uncommon. One scenario involved purchasing 10 brand-new automated waste collection trucks at $365,000 each. In this short article, not all the details can be discussed; however, it is easy to understand how many variables are included in the financial calculations. The new trucks included a warranty and free maintenance for a year. After that, spare parts and maintenance costs had to be factored in.

The financial analysis shows that the project is not beneficial after the first year. Therefore, a more detailed financial analysis was requested. Simple three- and five-year NPVs were calculated, as shown in Fig. 5.

Figure 5

NPV Calculations

The analysis clearly shows that the NPV is negative after three years, but some benefits could be expected after five years. Therefore, the payback period (PbP) had to be calculated precisely, as shown in Fig. 6.

Figure 6

Payback Period Calculations

The reader will notice that this is a straightforward PbP calculation, excluding potential inflation calculations, spare parts, and maintenance costs after the first year. Therefore, the company requested a complete financial analysis. Following two meetings with various levels of company management, a worksheet was developed to estimate the project’s economic benefits. Typical business tools and statistics were used to create the worksheet shown in Fig. 7. Notice that there are slight differences in values. The worksheet in Fig. 7 includes spare parts, maintenance costs, and 7% interest rate costs.

Figure 7

Financial Analysis

An interest rate of 7% was requested by the company. This was not a realistic interest rate at the time of the assessment. However, conservative estimates were required for this project. The worksheet and the built-in formulas allow for interest rate adjustments. The worksheet also includes IRR calculations. The IRR is a rate of return used in capital budgeting to measure and compare the profitability of investments. The IRR is calculated at 11%. For some companies, an IRR below 12% is not acceptable.

The payback period of 4.1 years was still unacceptable for the business managers. To capture other benefits and convince management, a new Lean Six Sigma tool was developed to measure productivity efficiencies. The current state PCE was evaluated and compared to the future state PCE. A combination of Six Sigma “suppliers, inputs, process, outputs, customers” (SIPOC) and Lean value stream mapping tools were utilized to present the benefits of the project (Fig. 8).

Notice the payback period. Organizations, financial professionals, and corporations commonly use the payback period to calculate investment returns. The upfront costs and the payback period became complex topics for discussion. Therefore, the EHS team used LSS tools to demonstrate productivity improvements to convince upper-level management that such an investment is justifiable from an economic, safety, and sustainability standpoint.

SIPOC and PCE were used. SIPOC diagrams are visual tools that map out a business process. PCE is a key metric in Lean Manufacturing that measures the percentage of time spent on value-added activities within a process. It is a simple formula, as shown in Eq. 1, and is calculated by dividing the value-added time (VAT) by the total lead time (TLT) it takes to complete the process.

PCE calculation:

Figure 8

Current State SIPOC and PCE

A modified fishbone diagram was used to present VSM because it is easy to use, understand, and visualize.

In addition, it was noticed that the project may have non-financial benefits as well. A concern existed for emissions from the refuse trucks. Therefore, the EHS team measured the emissions from the diesel refuse trucks. Another company that already implemented automated CNG trucks was kind enough to allow the authors to sample the CNG emissions for comparison purposes. Diesel emissions were higher in all categories for the older type of trucks measured. Substantial emissions reduction played a significant role in the decision-making process. Figure 9 provides the airborne data and comparisons for both types of trucks.

 Figure 9

Air pollution – Sustainability

Switching to CNG presents opportunities from a sustainability perspective. Technically, CNG and renewable natural gas (RNG) are almost identical. CNG vehicles can run on RNG without any modifications. However, CNG and RNG differ in their origin. CNG is extracted from fossil resources, while RNG is obtained from organic waste such as landfills, sewage sludge, or animal manure.

As presented in this case study, switching to RNG is a way for waste management organizations operating fleets of vehicles to reduce their carbon footprint. Further risk assessment is needed; however, if fueling a refuse truck entirely on RNG is not practical, then blending with fossil CNG is possible. Even if a small percentage of RNG is used, it will result in an instant reduction in CO₂ emissions without the need to invest in any upgrades or modifications to the refuse vehicle fleet.

Sustainability and reducing COx, NOx, VOCs, and PM emissions can play significant roles in decision making.

Instead of allowing landfill gas (LFG) to escape into the air, it can be captured, converted, and used as a renewable energy resource. According to the US Environmental Protection Agency (EPA), using LFG helps reduce odors and other hazards associated with LFG emissions and prevents methane from migrating into the atmosphere and contributing to local smog and global climate change. From a business perspective, LFG capturing generates revenue and creates jobs in the community and beyond. The process is illustrated in Fig. 10.

Figure 10

Collection and Processing of LFG to Produce Methane for Refuse Trucks and Other Uses

Source: https://www.epa.gov/lmop/basic-information-about-landfill-gas

Process improvements were evaluated utilizing Lean Six Sigma tools and modified risk assessment methodologies. The same SIPOC and PCE worksheet was used to assess future state improvements and process efficiency.

Future state SIPOC and PCE worksheets are presented in Fig. 11.

Figure 11

Future State SIPOC

To assess and estimate risk reductions from the proposed plan, the team used PtD and risk assessment processes, which indicated significant decreases in MSDs, extreme temperature exposures, and the likelihood of fall hazards.

Due to implementing Lean practices, PCE improved from 17.41% to 47.50%. Possible EHS involvement in the process was evaluated. Based on the comparison calculations, PCE increased from 17.41% to 47.5%.

Significant reductions in EHS risks and increased sustainability/EHS improvements were also projected. As presented in Fig. 12, striped bowtie analysis for the future state visualizes risk reduction, which can help communicate risk to management and other stakeholders.

Figure 12

Future State Striped Bowtie Analysis

As shown in the striped bowtie risk assessment, the proposed EHS intervention was estimated to reduce high and moderate risk ratings to more acceptable low risk levels for employee injuries, operational delays, and overall financial losses.

The financial analysis estimated the PbP of 4.1 years and NPV as negative after 3 years, which were less-than-ideal results. Therefore, a more compelling argument was to communicate the importance of occupational risk reduction and sustainability opportunities. As a result, emissions reductions and sustainability played a significant part in the decision-making process.

3.1 Lessons Learned

To be successful, EHS professionals should develop management skills and diversify their knowledge to overcome difficulties during such projects. Significant investment projects, such as the case study presented here, are sometimes difficult to justify based on occupational risk assessment alone. Future leaders in the safety profession will have to develop risk assessment skills and demonstrate knowledge in financial management. In order to defend such projects, EHS professionals have to be familiar with a variety of risk management techniques, sustainability initiatives, LSS tools, and financial management principles. Being an expert in ergonomics is not enough to successfully complete complex projects. Complex projects require multi-disciplinary knowledge and cross-disciplinary management skills. Safety leaders have to become familiar with different organizational structures and the variety of stakeholders’ interests to complete such projects. EHS professionals have to be prepared to deal with various levels of organizational management and demonstrate the value of sustainable projects.

EHS professionals can and should play a significant role in developing new business plans and sustainability initiatives that incorporate PtD, as well as implementing Lean Six Sigma practices designed to minimize injuries, improve productivity, and reduce wasted time. The PCE for this particular case study was improved significantly. The refuse collection process was made safer due to input from the EHS professionals. The project led to a decision by management to purchase new, safer, and sustainable refuse trucks, which presents opportunities to reduce injuries, reduce emissions, and improve productivity. BCSP’s new ASP/CSP blueprints present great opportunities for EHS students and early-career professionals to improve their knowledge and skills.

It was concluded that sustainability could significantly affect occupational, operational, financial, and strategic risk management decisions.

To answer the research question, the presented case study demonstrates that PtD methods can be successfully applied in environmental, safety, and sustainability improvement projects.

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