PPE Selection Must Address Concurrent Hazards
When multiple hazards exist such as the potential for skin contamination and heat stress, barriers designed for one such hazard may increase the potential for exposure to another hazard. Any type of barrier, while providing protection for one particular hazard may impact or degrade barriers established for other concurrent hazards that may need special considerations.
While increasing PPE to impermeable levels provides improved protection against skin contamination, in this case it also creates increasing conditions for exposure to heat stress.
A reasonable compromise must be implemented with additional precautions and barriers to mitigate the risks and exposure of concurrent hazards because no exposure to a hazard should be viewed as acceptable.
Effects of Incident:
Radiological Skin Exposure
An experiment requiring skin contact protection from radiological chemicals was being conducted. Elevated ambient temperatures, coupled with the physical nature of the work conditions caused concerns about heat stress (first hazard). Double layers of breathable skin protection were use that caused excessive perspiration to compromise the integrity the PPE coveralls resulting in several instances of skin contamination (second hazard). An investigation revealed that excessive worker perspiration enabled the migration of removable contamination through two layers of breathable Quantum Wear coveralls used for protection against skin contamination. A concern for heat stress influenced workers and management to delay use of impermeable (i.e., Saranex) type PPE, prior to the incident.
This was an effort to reach a reasonable balance between contamination protection and to prevent personnel heat exposure and physical injury to personnel dressed out in double polypropylene (i.e., Quantum Wear brand) coveralls for a balance of protection and ventilation.
Despite indications of chemical wicking through the PPE due to perspiration during another similar event and recognition of continued elevated ambient temperature conditions within the facility, additional barrier precautions to prevent further skin contamination events were overshadowed by the heat stress considerations.
Corrective Actions to Prevent Reoccurence:
- Under these conditions, a reasonable compromise needed to be determined and issues due to the compromise needed to be addressed by other additional barrier methods such as training, procedures, exposure time, sleeves, aprons, etc.
- Impermeable PPE for targeted areas (sleeves, aprons, knee pads, kneeling pads/mats) can offer the needed increased level of protection, while minimizing added heat loading.
- Look for engineering solutions to address concurrent hazards. For example in this case the work area may have been amenable to cooling to reduce the possibility of heat stress and allow impermeable PPE to be used.
- Determine which is the more dangerous hazard requiring control. In this case exposure to radiological chemicals was more dangerous than heat stress. Therefore heat stress may have been better controlled by incorporating additional controls such as rest periods and/or cooling the area.