PHOTOS: San Juan Generating Station through the decades

The San Juan Generating Station is pictured in 1978 prior to the completion of unit 4 in Waterflow.

A stack is pictured in 1978 at the San Juan Generating Station while unit 4 was being constructed.

Stacks are rebuilt in 1978 after an explosion at the San Juan Generating Station.

Cooling towers are pictured in 1978 at the San Juan Generating Station.

Sulfur dioxide scrubbers were installed in 1978 at the San Juan Generating Station to reduce emissions.

Employees check into work in 1988 at the San Juan Generating Station.

Public Service Company of New Mexico celebrate San Juan Generating Station Unit 3 running 365 days without an outage in May 1995.

The San Juan Generating Station is pictured in the 2000s in Waterflow.

The San Juan Generating Station is pictured in 2005 in Waterflow as the U.S. Senate debated mercury emissions.

A billboard in 2005 protests emissions from San Juan Generating Station.

The San Juan Generating Station is pictured in 2005 in Waterflow.

The San Juan Generating Station is pictured in 2011 in Waterflow.

The San Juan Generating Station is seen on Nov. 6, 2013, in Waterflow.

The San Juan Generating Station is pictured in January 2013 through the trees in Waterflow.

Steam billows from the San Juan Generating Station in January 2013 in Waterflow.

The San Juan Generating Station is pictured in April 2013 in Waterflow.

The San Juan Generating Station is pictured, Monday, Sept. 29, 2014, in Waterflow.

The San Juan Generating Station is seen, Monday, April 20, 2015, on County Road 6800 in Waterflow.

Tom Fallgren, plant manager at the San Juan Generating Station, stands near the power plant, Monday August 1, 2016, in Waterflow.

The San Juan Generating Station, as seen Monday August 1, 2016, in Waterflow.