The court filing said Monsanto agreed to plead guilty to 30 environmental crimes after workers were allowed to go into corn fields last year on Oahu after glufosinate ammonium-based product named Forfeit 280 was sprayed on the fields.
Federal law prohibits people from entering areas where the chemical is sprayed within six days of application.
The company will also plead guilty to two felony crimes related to the storage of a banned chemical on Maui, according to the Department of Justice.
"Monsanto is a serial violator of federal environmental laws," U.S. Attorney Tracy Wilkison said in a statement. "The company repeatedly violated laws related to highly regulated chemicals, exposing people to pesticides that can cause serious health problems."
Monsanto faces three years of probation in addition to the fines and continue a "comprehensive environmental compliance program" overseen by a third-party auditor, said the statement from the U.S Attorney's Office in Los Angeles, which is handling the prosecution.
"The defendant in this case failed to follow regulations governing the storage of hazardous wastes and the application of pesticides, putting people and the environment at risk," said Scot Adair, Special Agent in Charge of the Environmental Protection Agency’s criminal enforcement program in Hawaii, which conducted the investigation.
Monsanto apologized in a statement but said no adverse health effects had been reported to company officials in association with the violations.
"The conduct at issue in the agreement is unacceptable and contrary to the values and policies of the company, and we sincerely regret it," said Darren Wallis, Monsanto's vice president of communications for North America crop science.
The company said it will change procedures and training.
The Department of Justice statement said Monsanto has agreed that company representatives will appear in court to enter guilty pleas for the offenses "in the near future."