Background: The following case study involves a company with operations in industrial manufacturing. The case study will focus on a heat-treating facility. The process entailed open-room exhaust of natural gas-fired furnaces and open-room exhaust of endogas (a carbon rich atmosphere used in heat-treating furnaces). Once exhausted to the room, the only ventilation was achieved through axial roof fans.

Hazard Identification

The hazard identified with this particular industrial manufacturing operation involved carbon monoxide (CO) exposure to employees working within a heat-treating facility. CO is a poisonous gas that is odorless, colorless, and tasteless. Carbon monoxide is harmful when inhaled because it displaces oxygen in the blood and deprives vital organs such as the heart and brain from receiving oxygen. CO poisoning can be reversed if caught in time, but even with recovery, acute poisoning may cause permanent damage. OSHA standards prohibit worker exposure to more than 50 parts per million (ppm) over an 8-hour time-weighted average (TWA).

Hazard Intervention

The company identified the hazard as a chemical exposure to employees. The abatement approach involved a change in the administrative and engineering controls. Data points for CO were routinely collected and administrative controls were implemented as necessary. The corporate goal for CO levels was less than half of the TLV for CO (12.5 ppm). This goal was reached by implementing local exhaust ventilation (LEV) as the primary engineering control. All CO emission points (burner exhausts and endogas exhausts) were identified and targeted for LEV source controls. A ventilation system with variable-speed fans controlled by real-time direct reading electrochemical sensors for CO was installed in the heat treating facility.

Impacts of the Intervention

There were many positive health, business and risk management results from the implementation of the engineering controls. Health improvements resulted from the intervention because employees were not directly exposed to CO. Employees were healthier, happier, and more comfortable in the workplace. Health-related absenteeism was reduced drastically. Employee morale increased significantly, improving the quality of the work. The business process was improved because there was a reduction of CO concentration in the heat treat.

While this project did not demonstrate a significant financial payback, many benefits resulted from it.  The project demonstrated the leadership commitment to HSE. A major facility aesthetic improvement resulted because all of the smoke and haze were properly exhausted through the LEV system under a state-permitted emission source. There were no changes in product quality or customer satisfaction or service resulting from the intervention.

Financial Metrics

The project’s capital requirements were $1.6 million to install the ventilation system. The intervention resulted in a negative net present value (NPV) of -$1,005,597. The internal Rate of Return (IRR) was -25% while the return on investment (ROI) was -56%. Utility costs associated with running the IH-related equipment were expected to increase once the intervention was in place.

Lessons Learned

Retrospective analyses do not provide the opportunity to evaluate the costs and benefits of alternative hazard control solutions, but even in negative cost situations IH value can be demonstrated.  In this case, the heat-treat operation was an ultimate financial negative but a health, morale, and productivity positive.   The benefits were valuable to management, and in time will very likely be shown to have financial payback as well.