All the microbes you can’t have

Scientists have engineered microbes that can eat plastic, detect landmines and leach metals from ore. It sounds like science fiction, yet nearly all of them are locked away in the lab. The reason is not the technology — it is an American law written in 1976 for industrial chemicals.

A misfit law

In 1983, the US company AGS wanted to release a modified microbe to keep frost off crops. An activist named Jeremy Rifkin sued, and once the case blew up, White House staff decided that since genomes are made of chemicals, engineered microbes with tweaked genomes should also fall under the Toxic Substances Control Act (TSCA).

From then on, any microbe built with cross-genus DNA requires approval from the Environmental Protection Agency (EPA). Between 1987 and 2018, of the 240-plus applications filed, only a handful were approved. Companies often never learn why theirs were rejected, because the EPA has never published a checklist.

Who pays the price

A PET-degrading bacterium found in Japan was too slow to be useful, so engineers built FAST-PETase, a variant that works in under 24 hours. But putting the gene back into a living cell triggers TSCA. Engineered strains that detect heavy metals or leach rare earths can't leave the lab either.

Yet the same microbes escape the trap if they change use: those for pesticides, food or drugs go to different offices. A probiotic drink that breaks down acetaldehyde after drinking and a cavity-preventing mouth bacterium both reached consumers by slipping around TSCA.

The caution of forty years ago

In the 1980s, worrying that released microbes might multiply uncontrollably or swap genes with natives was reasonable. But four decades of data show most engineered microbes die off quickly in the environment. Even so, the EPA treats microbes more harshly than chemicals — it has even revoked exemptions for small-scale experiments that chemicals enjoy.

Brazil has approved engineered mosquitoes that cut wild dengue-carrying populations by up to 96 percent. Israel approves field releases in a few months. Fixing the US system could be as simple as an EPA memo — yet that memo never comes. Researchers argue for regulation that sets clear data and trial standards rather than an outright ban, so that safe, beneficial microbes can finally do their job.