Define Safe

You smell the stall before you see it. Brine, metal, river bottom, a smell that belongs on the coast. It stands among the pillars under the highway: gray-green water in plastic tubs, taped CREEK, RIVER, THE END OF CONGRESS, and over each tub a sensor on a stalk, built from parts that still carry their shipping labels. A sign: WE ARE NOT SELLING FISH. WE ARE MEASURING.

A boy points at a tub. Is that safe to touch? Define safe, says the woman behind the table.

She takes your jar, pours a finger of it into an empty tub, and waits for the stalk to settle. Battery runoff, she says. Scooters, a pallet of them, dumped behind a lot on Seventh after the rain. She hands back the jar, a finger short. Who do you work for? you ask. Whoever's downstream.

A placard has a printed square and three lines under it: the one who samples, the crews who clean up, a legal fund. Why legal? the boy asks. She shows him a letter in a plastic sleeve, a lawyer's name across the top and the date left blank. In case the city tells us to stop, she says.