Watch: This Widely Used Pipe Repair Technique May Pose Health HazardsDavid Wagman | August 01, 2017
New research is calling for immediate safeguards and the study of a widely used method for repairing sewer-, storm-water, and drinking-water pipes to understand the potential health and environmental concerns for workers and the public.
The procedure, called cured-in-place pipe repair, or CIPP, was invented in the 1970s. It involves inserting a resin-impregnated fabric tube into a damaged pipe and curing it in place with hot water or pressurized steam, sometimes with ultraviolet light.
The result is a new plastic pipe manufactured inside the damaged one. The process can emit chemicals into the air, sometimes in visible plumes, and can expose workers and the public to a mixture of compounds that can pose potential health hazards, says Andrew Whelton, an assistant professor at Purdue University’s Lyles School of Civil Engineering and the Environmental and Ecological Engineering program.
He led a team of researchers who conducted a testing study at seven steam-cured CIPP installations in Indiana and California. The researchers captured the emitted materials and measured their concentration, including styrene, acetone, phenol, phthalates, and other volatile (VOC) and semi-volatile organic compounds (SVOC).
Results from their air testing study are detailed in a paper appearing in Environmental Science & Technology Letters. The study files can be downloaded for free and are open-access.
Findings show that the chemical plume, commonly thought of as harmless steam, was actually a complex mixture of organic vapor, water vapor, particulates of condensable vapor and partially cured resin, and liquid droplets of water and organic chemicals.
“CIPP is the most popular water-pipe rehabilitation technology in the United States,” Whelton said. “Short- and long-term health impacts caused by chemical mixture exposures should be immediately investigated. Workers are a vulnerable population, and understanding exposures and health impacts to the general public is also needed.”
The researchers have briefed the National Institute for Occupational Health and Safety (NIOSH) about their findings. NIOSH is part of the Centers for Disease Control and Prevention and has occupational safety and health experts who can investigate workplace hazards.
Purdue researchers captured the chemical plume materials from two sanitary sewer-pipe installations and five storm-water pipe installations. Samples were analyzed using gas chromatography, thermal, and spectroscopic techniques. Chemicals found included hazardous air pollutants, suspected endocrine disrupting chemicals, and known and suspected carcinogens. Emissions were sometimes highly concentrated and affected by wind direction, speed and the worker’s activities.
A waxy substance was found in the air, and materials engineers determined it was partially cured plastic, styrene monomer, acetone, and unidentified chemicals.
To evaluate chemical plume toxicity, pulmonary toxicologist and assistant professor Jonathan Shannahan and a graduate student exposed captured materials to mouse lung cells. Plume samples from two of four sites tested displayed toxicity effects and two did not.