SAN FRANCISCO -- Is your tote bag making you sick?
A research paper published last year by professors at the University of Pennsylvania and George Mason University found San Francisco's ban on plastic bags has had significant negative repercussions on public health.
The study, released in August, found a spike in San Francisco hospital emergency room treatment due to E. coli infections and a 46 percent increase in deaths from foodborne illness in the three months after the bag ban went into effect in 2007. E. coli bacteria, common in the human intestine and frequent suspects in food poisoning, can range from harmless to lethal.
Laws against plastic bags often encourage the use of reusable totes to transport groceries. But as people tend to neglect washing those bags, increased food contamination becomes likely.
"Using standard estimates of the statistical value of life," the study's authors point out dryly, "we show that the health costs associated with the San Francisco ban swamp any budgetary savings from reduced litter."
San Francisco was one of the world's first major cities to pass a ban on the use of non-compostable plastic bags. The measure was gradually phased into effect, with full enforcement in 2012. Retailers are allowed to sell sturdier, compostable, easier to recycle plastic bags, as well as their paper counterparts, for 10 cents each.
The study's findings echo a 2011 paper conducted by researchers at the University of Arizona and the Loma Linda University School of Public Heath. In that study, the authors looked at reusable shopping bags taken from randomly selected individuals at California and Arizona grocery stores, identifying E. coli bacteria in 8 percent of all bags surveyed. However, washing the bags, either by hand or in a washing machine, eliminated 99.9 percent of the pathogens.
Interviews for that research revealed about half the individuals surveyed used their bags more then once per week, three-quarters didn't separate meats from vegetables and only 3 percent cleaned their bags regularly.
The study was harshly criticized by environmentalists, as its authors received monetary support from the American Chemistry Council, a trade group representing the interests of plastic bag manufacturers.
Many plastic bag ban proponents said the new study is also largely inaccurate.
"[Its] assertions are completely ridiculous and unfounded," Jennie Romer, Atlantic region director of the Clean Seas Coalition and founder of PlasticBagLaws.org, told The Huffington Post. She said the study focused on a period before the ban took effect, "so this data would not be relevant."
San Francisco is one of over 40 municipalities in California that have enacted bans on plastic bags. Assemblyman Marc Levine (D-San Rafael) recently proposed a a bill that would ban plastic bags statewide at all large grocery stores and retail locations. "To continue the use of these bags would ignore the convincing body of global evidence proving that these bags are having a drastic effect on marine ecocultures," Levine said in a statement. "Additionally, there are several easily available and affordable alternatives to plastic bags. We need to ban these bags once and for all."
Romer insisted that as people spend more time using reusable bags, they will understand that the bags need to be washed, much like dirty clothing.
A blog post on the The Learning Channel's website details some tips for keeping your reusable shopping bags clean, such as carrying bins for produce, separating meat and fish from other groceries to prevent cross-contamination and letting the empty bags air out after coming home from shopping.