FARMINGTON — A Philadelphia-based company has been hired to complete maintenance and modifications at San Juan Generating Station.

Day and Zimmermann, a family-owned construction and engineering business, was awarded the four-year contract. Work is scheduled to begin in November with support from Day and Zimmermann's Phoenix office.

"We selected Day and Zimmermann for its strong safety record and experience in improving work processes," said Tom Fallgren, the director of plant management at the generating station, in a news release. "Safety is a core value for (Public Service New Mexico), and D&Z is aligned with that value."

San Juan Generating Station plans to retire units two and three and install selective non-catalytic reduction technology, which are intended to reduce nitrogen oxide emissions, to units one and four.

Installing the technology to the two units will cost an estimated $60 to $80 million, said Ron Darnell, PNM's vice president of public policy in Farmington, in September. The New Mexico Environment Improvement Board has approved those plans.

This is Day and Zimmermann's first contract with PNM, which operates the generating station.

"This contract is an important step in our efforts to increase our fossil business and expand our geographic footprint," Gary McKinney, the president of Day and Zimmermann, said in a news release.