Published reports have questioned the safety of emissions from the cured-in-place (CIPP) process when using styrenated resin. Safety is NASSCO’s top priority and we have gone to great lengths to ensure our workers and communities stay healthy through the funding of comprehensive, third-party, objective research.

Phase 1: 

Study by the Center for Underground Infrastructure Research and Education (CUIRE) found previously published reports to be NON-CONCLUSIVE

Phase 2

Field studies in a variety of geographic locations -- testing different liner dimensions, conditions, and worker exposure – was conducted by the Trenchless Technology Center at Louisiana Tech University (TTC) and resulted in specific recommendations for refrigeration/storage trucks and emission stacks:                                                   

Liner Transport Trucks:

  • For those immediately entering the liner transport truck or storage unit, active air monitoring should be utilized at the initial opening of the truck or storage unit door to ensure a safe work environment.
  • At the initial opening of the liner transport truck or storage unit, suitable PPE should be worn by those immediately entering the truck or storage unit.

Emission Stacks:

  • A perimeter of 15-feet should be implemented around exhaust manholes and emission stacks during curing. This perimeter could be entered for short amounts of time not exceeding five minutes. If this area must be entered for longer than five minutes, suitable PPE should be used.
  • Emission stacks should be a minimum of six feet in height to enhance the dispersion of emissions and lessen the likelihood of workers entering the perimeter from having to cross into the plume even when wearing PPE

Phase 3:

Per TTC’s Phase 2 recommendation, an additional study is currently underway to focus on task-oriented worker exposure to emissions in identifying certain tasks within the typical 8-hour shift window that could pose health risks; to understand the dispersion of styrene from the liner truck after opening; and to correlate the number of liners being stored on the truck, the liner sizes, and the duration the liners have been on the truck with emission concentrations.

Other resources: