Purdue researchers test air emissions during CIPP installation.
SAFETY
Easy pipe repair method raises safety concerns JYLLIAN KEMSLEY, C&EN WEST COAST
W
hen a municipality repairs water or sewer pipes, it faces what seems like an easy decision: Dig up roads to replace the pipes entirely, or thread a tube of polymer resin through the damaged pipes, then inflate and cure the tube to create a new plastic pipe inside the old one. The decision to go with the second option is made even easier because the curing process appears relatively innocuous—it uses water, steam, or ultraviolet light. But studies of the process are starting to show that so-called cured-in-place pipe (CIPP) might not be as innocuous as it sounds. Over the past decade, researchers have found styrene and other suspected carcinogens leaching from the pipes and winding up in waterways. A study published earlier this year investigating steam-cured CIPP projects in the field additionally found that the “steam” emitted into the air during installation was actually a complex mixture of organic vapor, water vapor, particulates, and liquid droplets (Environ. Sci. Technol. Lett. 2017, DOI: 10.1021/acs.estlett.7b00237).
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ginia Department of Transportation told C&EN in 2015. After Whelton published research on the chemicals that wind up in water and steam condensate from CIPP installation, “All of the installation processes emit “homeowners and other people around the chemicals, based on our personal and country started calling and asking about field testing experience,” says Andrew J. air emissions,” Whelton says. When CIPP Whelton, a professor of environmental was being installed nearby, these residents engineering at Purdue University. Whelton smelled odors, and some said they became led the emissions study as well as some ill. When the people reported these effects of the research on CIPP water locally at the time, “They were told contamination. “Nobody really by municipalities and contractors understands the scale, complexity, that their exposures were safe and and quantity of emissions and the harmless,” Whelton says. Styrene scale of work-site or nearby public Those stories prompted Whelexposure,” Whelton adds. ton and his research group to look In CIPP installation, workers snake a for data to back up the claims that CIPP felt or fiberglass tube impregnated with process emissions were harmless. They polymer resin into the damaged pipe. found four studies of CIPP chemical air In the U.S., the resin is commonly styemissions, all of which detected styrene rene-based polyester and vinyl ester. Work- at potentially hazardous levels. They also ers inflate the polymer tube to line the pre- found dozens of incidents of CIPP-instalexisting pipe and then cure the polymer by lation-related air contamination in homes, circulating hot water or steam for several schools, and office buildings in Australia, hours. In some cases, workers may also use Canada, the U.K., and the U.S. costly ultraviolet light to cure the polymer. Whelton and colleagues went on to When water or steam is used for curing, monitor emissions from seven steam-cured the water or steam condensate should be CIPP installations in Indiana and Califorcollected and treated as waste—but worknia in 2016. They monitored air emissions ers often dump at least the water on-site, in real time and captured and condensed ecologist Bridget M. Donaldson of the Virairborne material for later analysis.
C R E D I T: P UR D U E U
Cured-in-place pipe fixes could lead to harmful emissions for workers and the public, research shows
They found a multiphase mixture of chemicals emitted into the air. The mixture included water vapor, of course, and also volatile organic carbon species, particulates of condensed organic species that included partially cured resin, and liquid droplets of water and organic compounds. The team measured levels of several specific compounds, including acetone, acetophenone, phenol, and styrene. Notably, the type and amount of chemicals varied for different CIPP installations, even for the same resin used in the same diameter and type of existing pipe. This variation would likely increase when comparing CIPP emissions involving different types of resin and curing materials. The team’s results also suggest concern for those working at CIPP installation sites. The researchers’ findings at two testing sites on the Purdue campus led them to start wearing full-face-mask carbon filter respirators during testing in California. Whelton also had nitrile gloves degrade from contact with uncured resin tube. Meanwhile, CIPP installation workers often did not wear respiratory or skin protection at sites Whelton’s team studied. In a statement responding to publication of the research, the National Association of Sewer Service Companies
“Nobody really understands the scale, complexity, and quantity of emissions and the scale of work-site or nearby public exposure.” —Andrew J. Whelton, environmental engineering professor, Purdue University (NASSCO) says, “It is clear that NASSCO guidelines and specific quality and safety protocols were not utilized during the testing performed. … This is of great concern to NASSCO and other organizations aligned to our industry that continually use, monitor and evaluate the effectiveness and safety levels of CIPP technology.” NASSCO has since requested proposals “to evaluate the potential release of organic chemicals in the steam exhaust and other release points during pipe rehabilitation.” Several municipalities and consulting firms, upon hearing of the research re-
sults, have contacted Whelton for assistance with addressing potential worker exposure. He in turn refers them to the U.S. National Institute for Occupational Safety & Health (NIOSH). CIPP concerns are new for NIOSH, and “anytime there’s a new process or emerging issue, NIOSH is interested in looking at it for occupational exposure,” says Rachel Bailey, a medical officer with NIOSH’s respiratory health division. “In the CIPP process, there seem to be a lot of volatile organic carbon species, including styrene, that are associated with mucus membrane irritation, blurred vision, headaches, fatigue, balance, and concentration.” When C&EN spoke with Bailey, NIOSH had received one request to do a health hazard evaluation for worker exposure related to CIPP. Following up on that request, NIOSH would typically look at processes and procedures and the types of personal protective equipment used and then determine how to assess exposure, Bailey says. “We proved that many of the assumptions that have been made for years about CIPP technology are incorrect,” with concerns for both workers and the public, Whelton says. “Worker safety organizations and health departments need to step up and start paying more attention.” ◾
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2018 SUMMER INTERNSHIPS Deadline: November 30, 2017
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