Unalaska’s biggest processing plant has agreed to pay a $142,000 fine for allegedly lagging on safety procedures meant to prevent chemical spills.

UniSea keeps large quantities of ammonia on hand for refrigerating fish, plus chlorine for treating its water supply. The Clean Air Act requires facilities to maintain a risk management program for those chemicals.

In 2010, the Environmental Protection Agency visited the plant in Unalaska to ensure that "they’re doing their due diligence to identify the hazards on site,” says investigator Javier Morales.

“And then, with that, mitigate those hazards by putting in safety systems, training their operators to fully understand the process equipment and what to do if there were a release to occur on-site," Morales says.

While the EPA can’t tell a company how to store its chemicals, agents found hefty containers of ammonia and chlorine at UniSea -- and that crossed a regulatory threshold.

"Which then kicks in a lot of requirements for them," Morales says. "There wasn’t any PHA, which we call a process hazard analysis. And there was no proper maintenance plan in place."

Building a case can be a lengthy process, Morales says. Since the investigation started four years ago, UniSea has changed its risk management program. And the EPA slashed their proposed penalty by more than half -- from $321,000.