Whoa! Before you pour that pan of tempura grease or french fry oil down the drain, think of what it will do to the sewer lines.

Usually, it’s "out of sight, out of mind." But oil will clog up the sewer.

What to do with this greasy waste? Pour it into a Whoa! Fat kitchen oil disposal box, that’s what.

It’s basically a leakproof Chinese takeout-style box filled with cellulose material that absorbs oil. It is made from recycled newspapers, phone books and cardboard.

Island Shell Environmental Manufacturing of Aiea, which also produces the Suck’Em Up Oil Change Boxes, makes the Whoa! Fat kitchen oil disposal boxes.

Brothers Chea and CJ Paet of CP Distributions LLC are the distributors for the product, which is available for $3 at Napa Auto Parts in Kaimuki and Hawaii Kai, and at Kale’s Natural Foods in Hawaii Kai Shopping Center.

The directions are really quite simple: Pour the oil from your frying pan into the Whoa! Fat box. If it’s not full yet, you can store it in the fridge or under the sink. When full, place the box in your gray trash bin for pickup.

The boxes can hold up to four cups, or one quart, of cooking oil. When they go to the HPOWER plant in the Campbell Industrial Park, the fats, oils and grease help produce energy.

It’s all pretty straightforward.

The Paet brothers are making it their mission to get a Whoa! Fat box into every residential kitchen on the island. They hope to take the boxes to the market nationwide.

Chea Paet, who also works as a property manager and real estate agent, says he has seen many condo associations deal with the high cost of sewer line repairs due to excess oil going down the drain.

"What we want to do is make sure the public knows what they do directly impacts sewer rates," he said.

When you pour grease down your sink, it cools in the sewer line and solidifies, forming clogs that can cause the sewer to overflow or back up into buildings, according to the city’s "Wastewater 101: A Primer to Our Wastewater System Treatment Process," published in 2010.

Fats, oils and grease — collectively known as FOG — are the city sewer system’s No. 1 enemy, according to the report. Grease might also cause your home plumbing to clog up.

If you want to learn what happens to Oahu’s wastewater, you can sign up for the city’s Tour de Trash, which is free and open to the public. The next tour will visit the HPOWER plant on May 12.

What’s also nice about the Whoa! Fat kitchen oil disposal boxes is that they are made in Hawaii. The materials are collected, recycled and manufactured here.

Nina Wu writes about environmental issues. Reach her at 529-4892 or nwu@staradvertiser.com.