Plastic bags are the superior grocery bag compared to paper.

1) Durability sure is an advantage, but plastic bags often fail to hold leaking contents. The bag is thin and during its usage, it's likely to get pierced or sustain small tears, and the leaking content then leaks through the bag as well. Liquid won't ruin the bag (as it is with paper bag) but it doesn't hold the liquid either, when carried around. In case of leakage, it's better to have plastic bag while carrying and paper bag when transporting, because even though the leakage destroys the paper bag, the paper helps at least a bit to absorb the liquid. 2) There are two types of plastic bags you might get in a store: a strong plastic bag with massive handles, and thin, bio-degradable one. Both can be used as small trash bag. The stronger type can be folded and kept and would serve the same purpose multiple times. The thin bag can be used too, but it's not very strong, damages quickly, (sometimes even on its own due its degradable properties), but it's wrinkly, messy to store and diffucult to fold. That's why they mostly end up in trash after first use. Paper bag technically can be reused for the original purpose too, though it's not common to see. It secondary use could be, that you can start fire with it, or use it as dust protection for documents but usually it ends up in the paper trash and can be recycled. 3) Paper doesn't go to land fill (and even if it did, it would degrade easily - depending on the chemicals contain in the paper or in its coating) . Paper per se can be recycled. And maybe they take bit more space prior to use, but not MUCH less, and also, are they are not significantly more expensive or complicated to transport. 4) Paper bags may cost more to produce, but less to recycle (and surely much higher percentage of paper bags are even recycled compared to plastics, which are usually burnt, because it's too much trouble to sort and clean). There are also costs on people's health - factory workers are exposed to toxins when these bags are produced, and also, when burnt. So if we calculate also with shorter life span of an economically productive person, sick days, and health care expenses, the economical aspect might very well be in favor of the paper bag. 5) It wasn't proven. There are recent voices that question that plastic bags are bigger burden to environment than others. Advocates of plastic bags have their own enviro-lobby, but reality is, the land and oceans are filled with waste and toxins from plastic bags. I don't have the standalone stats for plastic bags, but overall plastic waste in United States is estimated around 6.5% and 7.7% is used in waste-to-energy burning programs (2009 ^1). The rest ends up in landfills around the world where it takes 1000 years to decompose and at certain point leak toxins into soil and water. It"s estimated that there are also 100 millions tons of plastic debris floating around in the oceans threatening the health and safety of marine life. (2009). I'd like to note that plastic bags are harder to recycle (and therefore recycled in much smaller scale) than harder plastic containers as e.g. PET bottles, however, when it comes to recycling of plastic, they are never recycled in true sense - they can be transformed into other forms, but never go back to nature, like paper or compost. We're living in a plastic age. Plastic containers are cheap and massively used in several industries, but the west piles up and pollutes the world entirely, though predominantly the third world (^2) and international waters. Sources : ^1 - http://blogs.ei.columbia.edu... ^2 - http://www.salon.com...