The Spanish Fork City Council grilled developers about the safety of the Ensign-Bickford Co. land in a work session Thursday evening.

Ensign-Bickford and Presidio Capital are planning a mixed-use development on the land that once held the Trojan explosives plant. The company settled a legal battle with Mapleton City in 2006 over groundwater contamination stemming from the plant, which was decommissioned in 2006.

The land, which sits at the intersection of U.S. Highways 6 and 89 in Spanish Fork, is undergoing remediation which began in 2006.

Peter Barnett, president of Ensign-Bickford Co., addressed council members about the remediation efforts and tried to assuage any fears of further contamination. Although the site is still being cleaned to levels required for residential use, Barnett said great strides have already been made in the cleanup process.

"Right now, the site has been cleaned up to commercial/industrial criteria," he said.

The measures for cleanup are under a plan approved by the Utah Division of Solid and Hazardous Waste, and Jack Evans, managing partner of Presidio Capital, said representatives from the state have been heavily involved in ensuring the property is being cleaned up to standards.

"It's a process that we've been going through step by step and hand in hand with the regulating authority, which is the state," Evans said.

Much of the contamination comes from old settling ponds which were in the area for decades before they were removed by Ensign-Bickford. For such a long period of contamination, Barnett said, it takes time to completely clean the area. The company began thermal treatments of 100,000 tons of soil from the site in 2006, and an additional 40,000 tons were removed in 2007. Barnett said it does not take much heat, only a little more than a standard oven, to clean the soil.

Barnett said some soil will be remediated to a point where they will be permitted to place residential buildings, while others will be cleaned and remain open space. The open space requirements are not as stringent, but Barnett assured the council that all areas in the development will be safe for people to use.

A major source of concern for council members was possible water contamination in aquifers, which was the source of trouble for Mapleton residents. Councilman Wayne Andersen asked how the water would be filtered and how they could be sure it will be clean.

Evans reminded the council that the water problems mainly affected Mapleton because of the direction in which the aquifers flow. The flow is to the northwest, so by the aquifer's nature, Spanish Fork is largely unaffected. However, Evans said the company is filtering the water to clean out any contamination.

The water is being cleaned by carbon filtration, Barnett said, which leaves the water 100 percent drinkable. The contaminated water moves through recovery wells to a filtration system, after which it is pumped into the pressurized irrigation system.

Despite the measures taken to clean the water, Councilman Richard Davis expressed concern with building residential homes above contaminated aquifers. Davis asked whether the chemicals that had seeped into the ground from settling ponds could seep back up through the ground.

"With the remediation of the site, the geotech, the fault line and everything, we've already strategically placed these [homes] where they're clean and safe," Evans said.

On the Web:

• Updates on cleanup at the Ensign-Bickford site can be viewed at www.deq.utah.gov/Issues/EBCo.