Risks of Infrastructure Renovation: Bystander Injuries Due to Sewer Pipe Repair Emissions

By Andrew Whelton and Jonathan Shannahan, Purdue University

CIPP worksites help avoid long-term roadway shutdowns and traffic problems by repairing a buried pipe.

Complaints of illnesses, odors, and explosion have resulted in increasing calls of emergency responders to sewer repair worksites. Bystanders in nearby school, healthcare, office, and residential buildings have been affected, often describing noxious glue-like odors, headaches, nausea, vomiting, and other chemical exposure symptoms. In some cases, victims have required onsite medical treatment and been hospitalized, including children.

The most popular sewer repair practice, called cured-in-place-pipe (CIPP), is associated with these incidents. As communities expand sewer pipe repair efforts, increasing the likelihood of public health events, emergency responders must have a basic understanding of this practice and its chemical risks.

Cooking Plastic in Neighborhoods

To create a plastic CIPP, contractors bring raw chemicals onsite, insert them into the buried pipe, and then cure or cook those chemicals to manufacture a new plastic pipe. The most popular curing processes involve heat (injection by steam or hot water) or ultraviolet light (no water is used). CIPP is the least expensive pipe repair method available and a CIPP job can be completed in as little as two hours. Chemical resins used for CIPP are similar to those used in boat manufacturing. However, for boats the generated wastes are captured and treated inside factories. Boat manufacturing companies also report air pollution discharges to comply with federal and state laws.

CIPPs are created in buried sewer pipes, the waste is discharged into air through manholes and nearby sewer laterals, and the white material is plastic manufacturing waste, not steam.

The public safety risk of CIPP is associated with its direct discharge of untreated plastic manufacturing waste into the surrounding air and environment. Waste discharge has injured bystanders, contaminated buildings for months, and contributed to at least one indoor explosion. Contractors can add more than 25 psi pressure during CIPP creation, while only a few psi are needed to blow out water from building plumbing traps, causing waste to enter living spaces through sewer lines and drains. Waste can and has also entered buildings through windows, doors, foundation cracks, and HVAC system intakes.

The waste blown into the air can include uncooked resin, partially cooked resin, chemical saturated water vapor, particulates, semi-volatile organic compounds (SVOC), and volatile organic compounds (VOC) including styrene, benzene, acetone, methylene chloride, and others. An estimated six to 20 tons of VOCs can be released into air per project. Studies at Purdue University have revealed exposure to this waste is acutely toxic to mouse lung cells. Acute exposure is the primary concern for bystanders. The farther from the worksite, the greater chance the waste only includes organic vapors, not resin and particulates.

CIPP manufacturing waste can enter buildings through sewer pipes, open windows, doors, HVAC intakes, and foundation cracks.

What do Government Agencies Say?

Since 2017, various federal worker and public safety agencies have begun to take note of the increasing popular construction practice being used in neighborhoods nationwide. In 2017, an OSHA investigation revealed that a 22-year-old died on an Illinois worksite partly due to chemical overexposure. NIOSH studies have revealed worker safety chemical exposure limits being exceeded at multiple construction sites and noncompliance with OSHA safety standards. Florida and California state health departments have issued warnings about chemical exposures and bystander health impacts associated with CIPP.

12 Things to Expect if Responding to a CIPP Worksite

Backed by U.S. government agencies, we and our collaborators have conducted testing at CIPP construction sites, on the resins themselves, and created CIPPs in the lab. To this end, we have identified best practices for responding to incident sites to reduce exposures and injuries. These findings are important for emergency responders and health officials to understand.

  1. The primary health concern is inhaling the chemical waste products. Multiple instances of styrene levels at worksites and in sewers exceeding 1,000 ppm have been reported. The waste blown into the air at a steam CIPP worksite was determined to contain upwards of 4,000 ppm styrene. These levels exceed the IDLH concentration (700 ppm), levels where acute harm can occur for the general public (4.9 ppm), and where NIOSH recommends respiratory protection (500 ppm).
  2. Styrene is only one of many chemicals discharged into the air. Our toxicology study demonstrated chemicals that are in the air with styrene can be responsible and contribute to acute health effects. A sole focus on styrene places human health at risk since the emission is a chemical mixture.
  3. The material safety data sheets (SDS) do not list all the chemicals in the resins or those being created and discharged into the air. New chemicals are created that can cause acute health impacts.
  4. Odor should not be used to determine whether or not the exposure is safe for children, adults, and pets.
  5. Popular 4-gas meters cannot detect the chemicals discharged at CIPP worksites.
  6. Photoionization air testing meters (also called PIDs) cannot reliably quantify chemicals of concern at CIPP worksites. This is because the device is affected by the multiple chemicals present even if the device reports a single compound like “styrene.” The concentration of these devices can be 10 to 1,000 times off the actual chemical air concentrations.
  7. CIPP contractors use pressures that can displace or blow out plumbing trap water seals. One building may be contaminated, while the others nearby may or may not be. This is determined by contractor practices, sewer line and plumbing conditions, among others.
  8. Inside the building, levels exceeding the IDLH for styrene were predicted in some cases according to a new study. This condition would prompt responders to don respiratory protection in accordance with NIOSH recommendations.
  9. Following arrival, first responders should halt the CIPP process to gain control of the incident. Bystanders in other nearby buildings may also have contamination, but may not know or have called for help.
  10. Bystanders should be immediately removed from the exposure and seek medical attention. Counsel should be sought from public health departments, emergency medical technicians, and physicians, not CIPP contractors or their agents.
  11. Once the waste has stopped entering the building, ventilating the building can help with decontamination.
  12. If building ventilation starts before emergency responders arrive, under certain conditions chemical levels in the building may be drastically lower than what they may have been during the initial exposure that prompted injury or the explosion. Conversely, inadequate ventilation during CIPP waste entry may also cause greater amounts of chemicals to enter the building. The time needed for building decontamination will depend on the magnitude and location of the contamination (i.e., a building in Wisconsin required two months).

Actions to Take

To reduce risks posed to emergency responders and bystanders, public safety agencies can take several actions. Agencies are encouraged to petition public works and infrastructure owners who wish to use CIPP to require the capture of waste and/or use of less polluting practices. Requiring that the public health department be notified by the infrastructure owner before projects begin is also encouraged as the health department can track incidents. A free NIOSH health hazard evaluation can also be requested to better understand the hazards faced when needing to enter contaminated buildings and worksites.

CIPP can likely be used without endangering human health if appropriate controls are implemented. With the Infrastructure bill now signed into law, likely expanding the usage of CIPP, emergency responders should prepare their communities to avoid and address these incidents.

Andrew Whelton is a professor of civil, environmental, and ecological engineering at Purdue University and director of the Healthy Plumbing Consortium. Jonathan Shannahan is an assistant professor of health sciences at Purdue University. This article was partly based on a new study entitled “Emergency responder and public health considerations for plastic sewer lining chemical waste exposures in indoor environmentsfrom the Journal of Hazardous Materials. The study was funded by the National Institute of Environmental Health Sciences and National Science Foundation. Additional information on CIPP can be found at the Purdue University web site.