Arizona Public Services, Co. (APS) is preparing to clear contaminated dirt from a small parcel in Miami as part of a voluntary program to clean up eight manufactured gas plant (MGP) sites statewide that at one time belonged to corporate predecessors of the energy giant.

On April 8, the Town of Miami and APS entered into an agreement for cleanup of the Public Works yard — known as The Barn — behind CopperState Sanitation on Latham Boulevard and US 60. The remediation program has been in the works for the past two decades and the Miami site is one of the last locations on the list slated for cleanup.

“We realize it’s an imposition and were glad they’re allowing us to do it,” APS Community Affairs Manager Richard Rosales said. “We want to leave it better than we found it.”

The work is part of the Arizona Department of Environmental Quality (ADEQ) voluntary remediation program that “encourages property owners and other interested parties to invest resources voluntarily in recovering contaminated sites as quickly as possible to healthful standards. In return for such willing cooperation, ADEQ foregoes enforcement activity at the site.”

Rosales said that in addition to reducing liabilities for APS, remediation is “the right thing to do.”

The 2-acre site was at one time a manufacturing plant for synthetic gas that was owned by the Miami Municipal Gas Company. In the early 20th century, before natural gas became available, fuel for home heating and light was produced by reducing coal or oil to a gaseous form.

According to APS, MGPs operated from the 1800s to the 1940s and at one point there were more than 1,500 MGP site operating throughout the U.S.

There were 13 such sites in Arizona, and predecessors to APS operated eight of them. Over the course of time, APS sold the natural gas portion of its business, but retained responsibility for environmental impacts on the sites.

The Miami site was built in 1923 and operated by the Miami Municipal Gas Company until 1930, when it was sold to the Arizona Edison Company. Arizona Edison operated the MGP until 1940, but from 1940 to 1950 it was used as a natural gas storage site.

In 1952, Arizona Edison merged with the Central Arizona Light and Power Company to form APS. Twenty years later, in 1972, the Town of Miami took title to the property.

In the 1990s, APS began a concerted effort to clean up remnants of a past age.

“I’ve been working on it since the 1990s when we did the initial investigation,” Remediation Project Manager Judy Heywood said. “It takes a lot of prep work. The one we just finished in south Phoenix took 20 years.”

Heywood began her work in 1995 and in ’97, began to study and prioritize the sites for cleanup. The Miami site was far down the list because of its relatively tiny size and the small amount of material to be removed. The south Phoenix site required the removal of about 60,000 tons of soil as compared to the 5,000 to 6,000 tons — about 400 truckloads — Heywood estimates will be taken from Miami.

MGP byproducts include lampblack, residual oils and tars comprised of several compounds, including polyaromatic hydrocarbons and volatile organic compounds, according to material provided by APS. Health impacts require “long periods of exposure and [the compounds] are typically inert and do not biodegrade or migrate to the environment.”

“There is good news and bad news,” Heywood said. “It’s not water soluble, so it doesn’t leach into the water system. But it stays because it is not biodegradable.”

Initial assessments determined that there is no water down to at least 50 feet and the cleanup will be to the highest level possible.

“There are different cleanup levels: industrial and residential,” Heywood said. “We can use industrial as long as there is no water, but we’re going to use residential, which has a very high groundwater protection level.”

APS will test the soil down to 12 feet, although most of the material is within the 1- to 3-foot level, and Heywood expects to file an initial plan within the next few months. Once the plan has been submitted, there will be a call for public comment, and then there will be an “open house” to get feedback from the public. Once the public comment period ends, APS will respond and move forward once ADEQ approves the plan.

“We hope to submit in early summer and start work by September,” Heywood said. “The open house should be in July.”

Rosales said that all of the fiscal responsibility for the cleanup lies with APS and ratepayers will not pay for it with rate increases. ADEQ will bill APS directly for all associated costs, which will come from shareholder profits.

“It’s just the right thing to do,” he said.

The site is the only MGP that still has its original building and it is a working site for the Town of Miami, so the remediation will take that into consideration and work around scheduled uses for the building.

In addition, Rosales pointed out the economic benefits of the project, as workers will put money into the local economy through temporary lodging and attendant spending for the estimated two months the work is expected to take.

APS will also pave the property in an effort to “leave the site better than they found it.”

For information about the ADEQ voluntary remediation program, go to www.azdeq.gov/VRP.

For information about this project, contact Heywood at Judith.heywood@aps.com, or Rosales at richard.rosales@aps.com.

Pictured: The Barn, the Town of Miami’s Public Works yard, will have hazardous material removed by APS within the next year.

Photo by David Abbott