Hindsight is 20–20, or so defense lawyers like to say when their clients are caught poisoning thousands, sometimes millions, of people.

Such will almost certainly be the case once the class-action litigation over BPA finally heats up. The latest product to be found guilty of leeching the toxic pseudo-hormone into unknowing customers is ordinary point-of-sale receipts:

Cash register and other receipts may expose consumers to substantial amounts of bisphenol A, a hormone-mimicking chemical that has been linked with a host of potential health risks, according to a trio of recent studies.

On July 28, Warner and his colleagues at the Warner Babcock Institute for Green Chemistry in Wilmington, Mass., formally published their first data based on 10 receipts recently collected in the Boston area. Six contained 1.09 to 1.70 percent BPA by mass. Another two contained 0.30 to 0.83 percent BPA; the final pair had no measurable amounts. Their findings appear online in Green Chemistry Letters and Reviews.

A Swiss study published online July 11 in Analytical and Bioanalytical Chemistry assayed 13 European sales receipts. Eleven contained BPA in quantities ranging from 0.8 to 1.7 percent of the paper’s mass.

And that BPA rubbed off easily, notes study coauthor Koni Grob, an analytical chemist with the Official Food Control Authority of the Canton of Zurich. Just holding receipt paper deposited substantial BPA onto dry fingers.

Thankfully, it’s a minor problem:

Indeed, Grob says, “I think it’s a scandal that you can have people touching thermal paper all day long,” since the concentration of BPA in its surface coating could approach 10 percent pure BPA.

Frederick vom Saal of the University of Missouri in Columbia, who performed the BPA assays for a recent study by the Washington, D.C–based nonprofit Environmental Working Group, agrees with Grob.

“I won’t touch receipts now,” vom Saal says.

Or not.

So what are we supposed to do now, go about our daily lives wearing disposable latex gloves? Frankly, I wouldn’t mind that during cold and flu season, but something tells me cashiers are a bit suspicious of customers who don’t leave behind any fingerprints.

Hindsight, as they say, is 20–20. All of this research connecting BPA on receipts only came out last month, right?

Appleton Papers of Appleton, Wis., switched to one of them — bisphenol sulfonate — in 2006, notes Kent Willetts, a company vice president. As a steady stream of toxicity reports and research papers began pointing to potential health threats posed by BPA, “We decided that’s not a chemical we want to use.” EPA’s new partnership program lists the sulfonate as a potentially acceptable substitute, he notes.

Apparently not. Apparently some of the receipt manufacturers — for convenience, let’s call them the responsible manufacturers — recognized the danger more than four years ago, and so chose to make their receipts with a less toxic and less dangerous substitute.

And what was everyone else — for convenience, we’ll call them the irresponsible manufacturers — doing?

Attendees suggested using fear tactics (e.g. “Do you want to have access to baby food anymore?”) as well as giving control back to consumers (e.g. you have a choice between the more expensive product that is frozen or fresh or foods packaged in cans) as ways to dissuade people from choosing BPA-free packaging.

The committee doubts social media outlets, such as Facebook or Twitter, will work for positive BPA outreach. The committee wants to focus on quality instead of quantity in disseminating messages (e.g. a young kid or pregnant mother providing a positive quote about BPA, a testimonial from an outside expert, providing positive video, advice from third party experts, and relevant messaging on the GMA website). Members noted traditional media outreach has become too expensive (they have already spent hundreds of thousands of dollars) and the media is starting to ignore their side. The committee doubts obtaining a scientific spokesperson is attainable. Their “holy grail” spokesperson would be a “pregnant young mother who would be willing to speak around the country about the benefits of BPA.”

I see.

And they wonder why people want to sue them.