San Joaquin Farm Bureau Federation

By Vicky Boyd

When Al Dentone set out to register carbon dioxide as a more environmentally friendly fumigant for fruit, stored commodities and wood products, he never envisioned the arduous road ahead. More than 16 months after the Acampo resident submitted a registration package to the Environmental Protection Agency, it issued a product label in June 2016 to control pests of stored food and wood products. The California Department of Pesticide Registration took several more months, finally registering the CO product in April. Oregon and Washington followed shortly after.

“I didn’t realize how long it would take,” said Dentone, president of Inert Gas Injection LLC, or IGI LLC. He is still waiting for other labels.

In December, the Washington State Department of Agriculture approved the CO fumigant for use on certified organic agricultural products. 

A data package submitted to the EPA 16 months ago for use of CO to control burrowing rodents was rejected once before Dentone obtained the requested data and resubmitted it. He received word in late January that both the EPA and the California Department of Food and Agriculture approved an expanded product label that now also includes burrowing rodents. In addition, the expanded label states the fumigant is compatible with integrated pest management.

Carbon dioxide is found naturally in the atmosphere but at very low levels – about 0.04 percent or 400 parts per million. The CO Dentone markets, on the other hand, is 99.9 percent pure and is captured from ethanol fermentation. 

Through an arrangement with Airgas, an Air Liquide company, Dentone holds the exclusive contract for U.S. sales of the fumigant.

Because the CO2 is being used as a pesticide, suffocating its target and leaving no residue, it must be registered both federally and by states. The IGI CO2 is labeled for use to control beetles, moths and other stored-product pests on a myriad of fruit, dried fruit, nuts, grain and seeds. In addition, it is labeled for rail cars, silos, trucks and shipholds.

Unlike other fumigants, such as methyl bromide or phosphine, CO2 is much safer to handle, Dentone said. For example, the IGI product is not restricted-use. Nevertheless, he said commercial applicators and other users will need to undergo training.

The IGI CO is only half of his Elminator fumigation system. As an inert gas, the CO2 must be confined so lethal concentrations can be maintained.

Dentone also has an exclusive arrangement with Concord, Massachusetts-based GrainPro Inc. to be the exclusive Pacific Northwest seller of its patented TransSafeliner Gas-Hermetic Fumigation shipping container liners. The deal also covers the firm’s G-HF Cocoon bagging system for on-site treatments.

The airtight liners are sized to fit 20- or 40-foot containers. Users can install the liners quickly before the commodities are rolled in. After the products are loaded, users zip up the liner and hook up the CO2 cylinder. As CO2 fills the lined container, oxygen is pushed out through a vent on the top.

Once the gauge shows less than 3 percent oxygen, users shut off the canister, seal the gas port and close the container doors.

“The containers are typically in transport for two weeks,” Dentone said. “It takes seven days to kill everything, including the eggs.” The treatment should satisfy most export phytosanitary requirements, except if an importing country specifies methyl bromide fumigation.

In addition, the liner helps maintain internal low humidity and prevents condensation, which can play havoc with dried commodities.

GrainPro’s Cocoon is constructed of specially made durable plastic with low permeability to oxygen and CO2. They come in both standard and custom-made sizes to enclose stacks of crates, boxes or bagged produce. 

Fumigation is performed in much the same way as with the container liners. Depending on the temperature, commodity and target pests, treatment ranges from two to 10 days. 

But the products can be stored in the Cocoons for more than a year because what essentially is a modified atmosphere helps preserve quality and reduce spoilage, Dentone said. Users periodically check the oxygen levels and add more CO2 when oxygen levels hit 5-7 percent.

Although CO2 can be used on numerous commodities, Dentone said the product is sorely needed by certified organic growers, who have no organically approved fumigant to manage stored food pests. Their only option is to freeze their product, which can be costly.

He said he’s already had inquiries from large museums about using CO2 to treat some of their books, artwork and animal taxidermy for pests.

Cities also are interested in the fumigant to control the spreading bedbug epidemic, Dentone said. Furniture, bedding, clothing and other items that can harbor the pest can be put in a Cocoon for treatment.

“We know we can get 100 percent bedbug kill, along with the eggs, in 24 hours,” he said.

Dentone, who has a background in aquatic immunology, said he became interested in less toxic pest control methods several years ago when he developed a device for burrowing rodent control. The long pipe-like unit injected a mixture of oxygen and propane into rodent burrows, then ignited the gas to kill the inhabitant with large percussions.

Although the device worked well, Dentone said he had to stop using it because urban residents complained about the loud blasts. But it put him on a quest to find another environmentally friendly – but quieter – way to control the pests.