Look for critical clues about personal safety, starting with the “signal word” on the front of the label: caution, warning or danger (the most toxic). Signal words, required by the E.P.A. on registered pesticides, describe the product’s acute toxicity, its short-term hazard if absorbed through the skin, ingested, inhaled or contacting the eyes.
Next, read the precautionary label statements, and also what to wear when using the product. To prevent injury with the 20 and 30 percent horticultural vinegars, which have a danger rating, the best practice in personal protective equipment calls for fully covering skin with long sleeves and pants, as well as socks and shoes. Wear goggles or a face shield to protect eyes; a face mask, like an N95; and waterproof gloves. After spraying, rinse the outside of gloves before removing them, then carefully remove other gear and launder it.
This, especially, is the part that makes the Montana weed scientists and me uneasy, imagining gardeners in shorts and T-shirts, with maybe sunglasses on at best, having at the pigweed seedlings between the pavers.
“There are lots of different ways to manage weeds. Whatever you do, do it fully informed,” Dr. Mangold said. “If you don’t know, first ask for help.”
The nationwide cooperative extension system is there to answer questions, she reminds us, if only we ask — rather than go all “ready, shoot, aim” before we do.