FORTUNE — Wouldn’t it be nice to get paid for getting dressed in the morning? After all, wearing proper attire is part of the job, right?
Fat chance. First off, if you’re not putting on job-specific clothes in the morning — think a butcher’s smock — there’s no way you are getting a penny for pulling on a pair of pants. And as for those workers who do wear special uniforms, whether they get paid is subject to collective bargaining agreements, as designated by Congress in 1949.
The rule was cut-and-dried until December 2007, when 800 U.S. Steel Corporation (X) workers at a Gary, Indiana factory got a bit nit-picky. They filed a lawsuit arguing that the protective gear they put on before starting work — 12 or so items, including a flame-retardant jacket, a hard hat, earplugs, and protective boots — didn’t count as clothing and should therefore be exempt from their union agreement. They argued that clothes, as defined by Webster, are commonly worn for “decency or comfort,” not for protection.
The workers said they often spent as much as an hour a day “donning and doffing” the equipment and collectively sought back pay for that time.
The Supreme Court, which issued a 9-0 opinion in the case on Monday, was having none of it.
In writing the court’s opinion, Justice Antonin Scalia said that the court saw “no basis for the proposition that the unmodified term ‘clothes’ somehow omits protective clothing.” The justices ruled that U.S. Steel employees are bound to their collective bargaining agreement, which says they earn pay only for time at their work stations.
Monday’s ruling didn’t come as a huge shock to Mark Batten, a labor and employment lawyer at Proskauer Rose who has been tracking the case. It was, he said, an instance of one group of employees trying to “make an end run” around what is a pretty obvious rule.
But that didn’t keep industry groups from weighing in on what the case might mean for their business. In an amicus brief, the U.S. Chamber of Commerce urged the judges to reject the workers’ argument, as did the American Meat Institute. The Grocery Manufacturers Association said in its own brief that a ruling in the workers’ favor could mean it could cost as much as $1,500 for each of its millions of employees who often wear protection clothing and footwear. “The class action litigation and retroactive liability that would follow could be devastating to employers in the industry,” it said. Safe to say they’re no longer shaking in their steel-toed boots.