What’s one of the biggest barriers to maintaining the nation’s water infrastructure? Adequate funding, of course – many municipalities struggle to find enough resources to support their maintenance projects. But there’s another obstacle and it’s related to asbestos.
Roughly 200,000 miles of asbestos cement (AC) water mains were installed from the 1940s to the 1970s, primarily in the western and southern United States. Steel was in short supply in the 1940s because it was diverted to airplane and ship-building factories during World War II. At the same time, the suburbs were growing rapidly and new water infrastructure was needed to serve these areas. Civil engineers needed to find other materials that would hold up as well as iron or steel. They found that an asbestos-silica-cement composite was structurally strong and very durable, lasting 50 to 80 years. It was embraced by engineers and municipalities across the United States.
Experts estimate that about 15 percent of all potable water mains currently in use contain asbestos cement. On the West Coast, where the population grew rapidly in the post-war era, AC pipe makes up as much as 20 percent of all water mains and even more than 50 percent in some municipalities. Many of these mains are reaching the end of their lifespan but replacing them isn’t that simple. Regulations governing the replacement and disposal of AC pipe are unclear. Regulatory bodies often don’t agree on the removal and disposal methods of AC pipe. Moreover, there is no data that will give them the confidence to make more definitive rules governing AC pipe removal. Currently, the disposal of AC pipe falls under EPA’s guidelines which state that any broken or crushed AC pipe is a regulated material under the National Emission Standard for Hazardous Air Pollutants (NESHAP), the same regulation that governs the removal of asbestos materials in buildings such as wall insulation and ceiling tiles.
Lack of guidelines
EPA’s guidelines do not provide explicit procedures on how to handle broken AC pipe. Instead, it entrusts state and regional agencies with enforcing disposal regulations and these agencies are often not aligned on the issue. Regulations can even vary within a state and within local or regional agencies. For instance, regulation of AC pipe in California falls under 19 different agencies, all of which differ in their stringency.
Agencies also differ in how they regulate one of the more popular pipe rehabilitation methods. Pipe bursting involves breaking an old pipe in place while creating a cavity in the ground large enough to pull a new pipe into place behind the bursting head while it advances through the ground. For example, five states (Colorado, Massachusetts, New York, South Carolina and Utah) interpret EPA’s guidelines as a prohibition on pipe bursting. Other states require contractors with special abatement licenses to remove and dispose of AC pipe. While most states don’t expressly prohibit any particular method, many impose requirements related to notification and following EPA guidance related to Regulated Asbestos Containing Material (RACM).
Why is there so much variability in how these regulations are enforced and interpreted? In large part it’s due to a lack of data about the environmental and health and safety risks of asbestos pipe replacement, which makes it difficult for any single regulatory approach to win out. In approaching these projects, it’s helpful for contractors to understand the perspectives of various stakeholders involved. Some environmental regulators tend to be concerned that any broken AC pipe left in the soil could become an environmental hazard and thus advocate for costly disposal methods. It can be helpful to educate these stakeholders on the technical aspects of the pipe-bursting method. The name pipe bursting can also give the mistaken impression that the process involves blasting asbestos fibers into the air. It’s important for any engineer or contractor who is attempting to get approval for a pipe bursting project to educate regulators that the process does not free asbestos fibers, but instead leaves them in the ground where they are encapsulated in hardened cement and unable to do any harm to workers or the environment. In other words, asbestos encapsulated in cement behaves very differently from asbestos that is contained in fragile, easily friable materials like building insulation.
Nevertheless, until we have clear data that shows pipe bursting of AC pipe does not put workers’ health and safety or the environment at risk, the regulatory confusion on the issue will likely continue.
In an attempt to overcome this hurdle, Battelle has begun collecting data on the environmental impacts (if any) of AC pipe renewal during pipe bursting and other rehabilitation methods, including lining, in a project commissioned by the Water Research Foundation (WRF).
Battelle has been collecting soil, air and water samples from AC pipe bursting and lining sites around the country. So far the data shows that pipe bursting of AC pipe is safe. Test results reveal limits that are within federal environmental and health and safety standards.
This kind of on-site testing has been key to getting local regulators to feel more comfortable and confident in approving pipe bursting projects. In Casselberry, FL, for example, the air tests were used to reassure state regulators that the pipe-bursting process was safe.
The Battelle research will be completed this year, and the hope is that it will be used to bring forth more specific federal guidance that will make it easier for municipal engineers and contractors to rehabilitate aging AC pipe using a method that works best for them, including pipe bursting. The research will be available to everyone in the water infrastructure community to help them better understand the issues and risks associated with AC pipe renewal and to access the quantitative data to back it up.
In the meantime, it is suggested that doing tests locally can help with getting approvals on AC rehabilitation projects. The key is to engage and educate regulators early on, so they understand how the various renewal methods work and the risks they pose. Start by doing a project that is small enough to be exempted from federal environmental regulations (under 260 linear feet per year), and use that as an opportunity to conduct testing during the main replacement.
This is an incremental approach, but one that holds promise for getting the data that EPA and local regulators may need to enact policies that balance the need to protect public health while ensuring reliability of the water system.
ABOUT THE AUTHORS: Dr. Matthews and Dr. Vaiday are research scientists with the Water Infrastructure group at Battelle Memorial Institute. Each holds a Ph.D. in civil engineering from Louisiana Tech University.