A Dutch Harbor seafood plant employee has agreed to plead guilty to a Clean Air Act violation for tampering with machines designed to reduce nitrogen dioxide emissions.

Byran Beigh faces jail time over a single Clean Air Act tampering charge. The criminal case was filed Wednesday in U.S. District Court, and he agreed to plead guilty Thursday, according to U.S. Assistant Attorney Kevin Feldis. The charges accuse Beigh of encouraging others to falsify emissions records, as well as using a makeshift tool to alter the readings on water meters.

The alleged tampering happened from August 2009 to August 2011 when Beigh worked as the powerhouse operator at Westward Seafoods Inc.'s Dutch Harbor facility. The company declined to comment about Beigh's employment status or the measures it may have put in place to prevent further environmental violations.

However, the company previously agreed to comply with government standards after it paid a fine of more than $500,000 for ignoring inoperable pollution reducing devices, the same systems Beigh is now accused of tampering with, said Feldis.

Westward Seafoods began its operations in Dutch Harbor, the port and economic lifeblood in the Aleutian community of Unalaska, in 1991. The company is a subsidiary of Japanese-based Maruha-Nichiro Holdings Inc., which maintains a headquarters in Seattle.

The Dutch Harbor plant processes 254 million pounds of seafood each year. According to the criminal complaint filed against Beigh, the plant produces its own electricity with three-diesel-fueled electric generators, as well as steam for fish production using two diesel-fired steam generators.

Westward acquired a Clean Air Act permit through the Alaska Department of Environmental Conservation to operate the five power units that vent into a single smokestack. The permit required the installation of retrofit water injection packages on the three diesel generators to decrease nitrogen dioxide emissions. So the company set up systems that saturate the air with water, reducing the discharge of potentially dangerous gases.

The permit expires in September 2015, according to court documents.

As powerhouse operator, Beigh was tasked with monitoring and repairing equipment. Additionally, he and others were required to fill out daily reports. Proper procedure required employees to record the water levels of the saturation systems. However, "rather than write any of the … information, defendant Beigh, along with the powerhouse supervisor, instructed others to simply leave the (saturation system) section of the form blank or write 'OK,' " the complaint says.

The forms are submitted to the Department of Environmental Conservation and the EPA.

The powerhouse supervisor goes unnamed in the affidavit, but the charges say the manager "wholly fabricated" the numbers on the reports and the emissions reducing equipment was "scarcely operated from August 2009 to August 2011." Online court records show the company has not been charged in connection with Beigh's alleged actions.

"The investigation surrounding the false statements and tampering with the pollution control equipment at the Westward Seafoods powerhouse is continuing," Feldis said when asked if Westward may face separate criminal charges. The EPA directed all questions to the prosecutor.

To cover up the false entries, Beigh tampered with water meters so the numbers on the forms matched those being submitted to the company's environmental compliance manager for review, according to the charges.

New meters had been installed on the saturation systems, but water was not running through them. Beigh did not want anyone to see that the numbers on the meters -- "especially when they were new and all indicated zero" -- were inaccurate, so he used a drill press with a magnet on its end to cause the meter to spin, according to the charges.

A court summons was issued for Beigh at a Yakima, Washington address. Court documents indicate he faces two years in jail and a $250,000 fine. The court has not set a date for Beigh to enter his plea.

Westward Seafood in 2010 agreed to pay $570,000 for separate environmental violations. The civil penalty was part of an agreement with the government for Clean Air Act and Emergency Planning and Community Right-to-Know Act-related offenses.

The civil complaint from that case notes inoperable air pollution control devices tied to three diesel generators. From 2002 to 2006, the company burned 1.3 million gallons of diesel fuel with excess sulfur, the complaint says. The company also repeatedly failed to respond to inquiries from state and federal inspectors.

The planning act violations stemmed from accusations the company did not report to the community or appropriate agencies the use and storage of 80,000 pounds ammonia.