A multimillion-dollar plant expansion is in the works for Helena Industries in Des Moines.

Construction of a 20,000-square-foot addition could start as early as this week on the plant at 3525 Vandalia Road depending on the weather.

Plant manager Troy Hugen said the addition will house a manufacturing process for glyphosate, a common herbicide used on agricultural crops.

Hugen said the addition of the glyphosate process to the plant could bring 12 to 15 new jobs to the area.

The new project is scheduled to be completed by the third or fourth quarter of this year.

Helena Industries is partnering with an international firm on the project, but would not release the name of the client.

Exact volumes were not released, but Hugen said the addition is designed to produce more than 6 million gallons a year.

According to the Environmental Protection Agency, glyphosate is the most commonly used herbicide by volume.