(Bloomberg) -- As many as one in 12 cases of Covid-19 in the early stage of the pandemic in the U.S. can be tied to to outbreaks at meatpacking plants and subsequent spread in surrounding communities, according to a study.The findings show “a strong positive relationship” between meatpacking plants and “local community transmission” in cases through late July, suggesting the plants act as “transmission vectors” and “accelerate the spread of the virus,” according to the study by researchers at Columbia University’s School of International and Public Affairs and the University of Chicago’s Booth School of Business.The conclusions draw attention to the role of the meatpacking industry in the pandemic and the Trump administration’s controversial approach to workplace safety as outbreaks at slaughterhouses emerged. Trump issued an executive order on April 28 directing meatpackers to reopen closed facilities, and the administration eschewed mandatory Covid-19 safety regulation, opting instead for voluntary industry guidelines.Marc Perrone, president of the United Food and Commercial Workers Union, said the study “makes clear the Trump administration cares more about industry profits than protecting America’s frontline workers in the meatpacking industry.”“This is just more confirmation that without immediate action, deadly outbreaks at these plants will quickly spread across the Midwest and cause Covid-19 cases to spike even higher,” he added.Later ImprovementsSarah Little, a spokeswoman for the North American Meat Institute, an industry trade association, said meatpackers have invested “more than $1 billion so far, in significant changes and improvements regarding Covid-19 prevention” and the study doesn’t account for the impact later in the year.“The authors fail to capture the downward trend of positive cases associated with the meat and poultry industry into the summer and fall, especially in contrast to the positive cases reaching new highs around the nation,” Little added.Press representatives from the U.S. Department of Agriculture didn’t respond to requests for comment.Slaughterhouses quickly became hot spots of a pandemic initially centered in coastal urban areas, as the processing plants’ often poorly paid, heavily immigrant workforce labored in crowded facilities -- sometimes shoulder-to-shoulder. Even as health authorities urged social distancing and isolation of infected people, many plants offered perfect-attendance bonuses to discourage employees from taking sick days.By late July, the pandemic was shifting to rural regions in the country’s second wave of infections. States with a heavy presence of meatpacking facilities such as South Dakota, Nebraska, Iowa and Minnesota now have among the highest concentration of new cases by population. The virus is now spreading at record rates, with more than 12 million positive cases and more than 247,000 dead.The peer-reviewed study, published last week in the Proceedings of the National Academy of Sciences of the U.S., found that the risk of excess death was primarily associated with large meatpacking plants operated by industry giants. Communities that acted to temporarily shut down slaughterhouses reduced spread, according to the researchers.Community SpreadOverall, the researchers found 236,000 to 310,000 Covid-19 cases through July 21 associated with “proximity to livestock plants,” comprising 6% to 8% of virus cases at the time. Between 4,300 and 5,200 Covid-19 deaths were in counties near a large meat-processing plant, representing about 3% to 4% of U.S. deaths in that time period.“The vast majority” of those cases were “likely related to community spread outside these plants,” the researchers wrote.Residents of counties with meatpacking plants were 51% more likely to have contracted the coronavirus by July 21 and 37% more likely to die from the virus, even when corrected for risk factors including race, ethnic background, average income, household size, portion of workers in frontline jobs, elderly population and population in prisons and nursing homes, the researchers found.The researchers also found plants that received waivers from the USDA to increase their production-line speeds had relatively more county-wide cases. Earlier this month, the department submitted a proposal to raise maximum line speeds nationwide for chicken processing.“Ensuring both public health and robust essential supply chains may require an increase in meatpacking oversight and potentially a shift toward more decentralized, smaller-scale meat production,” the researchers concluded.Read More: Farm Industry Braces for Tougher Eye on Practices Under Biden(Updates with response from industry trade group in sixth paragraph)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.