Consumers aren’t the only ones who aren’t keen on a high-tech “solution” to GMO labeling.

As the Grocery Manufacturers Association (GMA) was meeting behind closed doors last week, trying to negotiate some sort of compromise that would preempt Vermont’s mandatory GMO labeling law before July 1, a number of Senators—including presidential candidate Bernie Sanders—sent some pointed questions for the GMA about its proposed QR code labeling scheme.

Sanders, along with Sens. Richard Blumenthal (D-Conn.), Chris Murphy (D-Conn.),  Ed Markey (D-Mass.), Jon Tester (D-Mont.) and Patrick Leahy (D-Vt.) fired off a letter to the GMA’s executive director, Pam Bailey, stating that they are “troubled” by the QR code scheme’s “anti-consumer loopholes.”

Here are their questions:

How will GMA ensure that consumers who don’t have smart phones—typically lower income, less educated, or elderly individuals—are able to access important food labeling information while they are shopping in grocery store aisles?

What promises will manufacturers participating in the SmartLabel initiative make to consumers to assure their privacy and their information will not be used or sold?

What steps will your members take to resolve these numerous technical considerations?

The Senators request a response by February 17, 2016.

Vermont’s GMO labeling law is at risk, if a federal bill preempts it with QR codes. Connecticut’s GMO labeling law can’t take effect until several other New England states pass similar laws. And Massachusetts currently has a bill under consideration, supported by 155 state legislators.

You can read the entire letter here. It pretty much sums up the reasons that consumers reject QR codes, and remain committed to requiring mandatory, on-package labeling of GMOs. Please tell your Senators you want mandatory, on-package labeling of GMOs—not QR codes!

Katherine Paul is associate director of the Organic Consumers Association.