“For want of a comma, we have this case.” So begins the recent twenty-nine-page 1st Circuit Court of Appeals decision in the case of O’Connor v. Oakhurst Dairy. For those of us who lament the modern trend of omitting the serial, or Oxford, comma, the Oakhurst Dairy case is an interesting story about how the absence of a simple punctuation mark could cost a dairy in Maine upwards of ten million dollars.

The dispute, which should have been straightforward, concerns overtime pay for the dairy’s drivers. Oakhurst argued that the drivers are not entitled to overtime pay because, according to Maine law, employees involved in “[t]he canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution of: (1) agricultural produce; (2) meat and fish products; and (3) perishable foods” are not protected by Maine’s overtime law.

The multi-million-dollar question of whether these drivers are or are not protected by Maine’s overtime law hangs on a comma — or, in this case, the lack of one. A comma after “packing for shipment,” would have made it clear that “distribution” is the last of nine separate listed activities, and therefore employees who distribute the food would not be protected by the overtime law, but without a serial comma after “shipment,” the sentence becomes ambiguous. The “packing for shipment or distribution” can reasonably be read together as the eighth and final activity on the list and not as two distinct activities. In this reading, employees who pack products for shipment or distribution are excluded from the protection of the overtime law, but employees who drive the trucks that distribute the food are not excluded and are therefore entitled to overtime pay. It is a small difference, but a crucial one. The 1st Circuit resolved the ambiguity in favor of the drivers, taking the view that that the lack of a serial comma after “shipment” means that the drivers are not included in the list of workers excluded from Maine’s overtime law.

There is no hard-and-fast rule in society about the use, or omission, of the serial comma, but people who care about such things tend to have a strong opinion one way or the other. “AP Style,” which is used by most print news organizations, including the New York Times and the Wall Street Journal, does not use the Oxford comma, arguing that it is an unnecessary and frivolous use of space on the page. The Oxford comma is, however, commonly used in both academic writing and book publishing, and amusing examples of what can happen when you omit the Oxford comma abound: “This book is dedicated to my parents, Ayn Rand and God.” “We invited the strippers, JFK and Stalin.” “He interviewed Merle Haggard’s two ex-wives, Kris Kristoferson and Robert Duvall.”

This overtime-pay ruling is a less chuckle-inducing–and very expensive–illustration of how important a simple comma can be for clarity, and how a working knowledge of grammar and style guides such as Strunk & White’s classic “The Elements of Style” could have saved one company in Maine millions of dollars.