In A Pickle
Lets see where this series of events has brought us. USDA-ARS has done research to show that 20% concentrations of acetic acid work to control weeds. Many people are clamoring for access to products with these high concentrations, yet no company seems willing to go through the EPA registration process with a 20% product. Adding to the problem, it seems that some USDA personnel are locating sources of 20% product (distributors who sell 20% vinegar to food outlets) and recommending them to the public as sources of herbicide. We have received e-mails to this effect and have followed Web threads evidencing such recommendations.
Can those of us in extension take the same short cut and recommend the higher (unregistered) concentrations, or in fact give people lists of distributors? The answer, at least in Washington State, is NO. There is a legal fine point buried in here. If any material claims to kill pests (weeds) it becomes a pesticide, no matter who does the claiming. We cannot make a recommendation for an unregistered pesticide. Okay, so what if the material does not claim to be a pesticide, it is simply a food grade 20% solution (normally) sold to those who make pickles? Can we recommend it then? The answer is again, NO. As Ms. Sturgess pointed out, making lists of 20% vinegar outlets is tantamount to directing people to use an unregistered pesticide.
Some may ask what is the big deal over such picky paperwork details when people are clamoring to use the product? After all, isn't the catchphrase of the marketplace "Let the buyer beware"? Besides being legally culpable in recommending unregistered pesticides, we have practical safety concerns for homeowners. Homeowners are not trained in safe handling and storage of concentrated chemicals. Acetic acid concentrations over 11% can cause burns upon skin contact. Eye contact can result in severe burns and permanent corneal injury. The 25% acetic acid concentrations registered through EPA and the states for commercial use all have restricted entry intervals of 48 hours and list personal protection equipment to be used by the applicator. None of this safety information is included on the twist-tie information on the jug of Bradfield Horticultural Vinegar. Because the public is used to thinking of vinegar as something you can safely splash on your salad and eat they are generally unaware of potential dangers of a higher concentration.