The recent E. coli outbreak in romaine lettuce, which led to at least 210 people across 36 states growing ill, may have been caused by the rolling back of Obama-era FDA regulations by the Trump administration.

One outbreak earlier this year, which has been tied to nationally distributed romaine lettuce grown in Yuma, Ariz., caused kidney failure in at least 27 of the reported cases and the death of five people. The contamination from the most recent outbreak has been traced to the central and northern coastal growing regions in California, according to the CDC.

Scientists believe the outbreak began when contaminated irrigation water was used to water the crops. Although many people have discussed how the water became contaminated, former physician and Twitter activist Dr. Eugene Gu detailed how the Trump administration is to blame in a detailed thread.

Right now the FDA does not require that irrigation water be tested for dangerous pathogens such as E. coli. In 2011, the Obama administration created policies that would have forced farmers to begin testing for such contaminants starting this year.

However, six months before the most recent E. coli outbreak, the Trump administration delayed the new regulations for at least four more years.

Dr. Gu tweeted about how Trump’s action to delay the policy may have directly affected the spread of contaminated produce. Gu, who once successfully sued the president for blocking him on Twitter, is no stranger to taking on the Trump administration.

Despite being praised for his vocal critique of the president, Gu was not applauded for his stance at his place of work.

Earlier this year, Gu, 32, lost his job at Vanderbilt University Medical Center. Although Gu was supposed to have a five-year surgery residency, the hospital ended his contract after only three years.

“The take-home message here is that there is an unwritten rule for surgical residents and that is rule is, always make your program look good and always make your hospital look good, and often that means stay silent,” Gu told the Tennessean. “But as an Asian-American physician, unlike a white doctor, I don’t always have the same luxury to stay silent."

Irrigation water is often the culprit for the spread of food-borne pathogens such as E. coli and can be especially effective on produce often eaten raw, like lettuce. Something as simple as fecal runoff from nearby livestock can taint local water supplies, such as the aforementioned canal, and then that water supply, when transported unfiltered and untested to be used in irrigation, is spread over produce—produce that is then harvested and sold.