Maryland Gov. Larry Hogan (R) signs a bill creating licenses for blow-dry services. Behind him, Del. Ariana Kelly (D-Montgomery) points and Drybar founder Alli Webb looks on. ( Daniel Swartz/ )

PUNS AND quips abounded after the recent bill-signing ceremony in which Maryland Gov. Larry Hogan (R) inked a measure that reduced licensing requirements for personnel at “blowout” salons, whose services are limited to washing and blow-drying hair, as opposed to cutting hair, as at a full-service salon. The bill itself acquired the nickname “license to blow,” and some openly wondered whether the patently close-cropped Mr. Hogan had enough personal experience to weigh in on the issue.

Fun’s fun, and far be it from us to pour cold water on this hot topic. (Sorry.) But there is a serious reason to praise the new measure: It represents a modest but genuine step toward reform of occupational licensing rules that too often stand in the way of career progress for working Americans, and not only in Maryland. Last year, a White House report documented the startling fact that 1 in 4 U.S. workers need a license to do their jobs, a fivefold increase since the 1950s. Many licenses can be obtained only after spending many months, and thousands of dollars, on training — and paying stiff fees. These burdens weigh especially heavily on ex-offenders and members of military families, the report found.

Some of this growth, to be sure, reflected expansion in the health and education sectors, with their necessarily licensed teachers, doctors and nurses. Overall, however, the White House report found that two-thirds of the growth in licensing over the past half-century was due to proliferating state laws, not changing workforce composition. Many of those state laws seem designed to protect incumbent businesses, not consumers. Even where there is a health-and-safety argument for occupational licensing, the requirements vary from state to state according to no particular logic.

The new Maryland bill creates a “limited” cosmetology license for workers in blowout salons; it can be obtained after 350 hours of training. Previously, you had to be licensed as a stylist or cosmetologist, which require 1,200 and 1,500 hours of training, respectively. Even 350 hours seems onerous for a job that many people can undoubtedly master in far less time; ditto for the higher-level hair-care licenses. Yet Maryland’s hair-care licensing rules were in fact relatively permissive even before the new law, according to a 2012 study by the Institute for Justice, a libertarian think tank. In Iowa, for example, you need 2,100 hours for a cosmetology license; by contrast, Massachusetts requires only 1,000.

Blowout bars disrupted the salon industry — to the apparent benefit of consumers and entrepreneurs alike. To the extent there are still irrational licensing barriers in their way, those should be removed. If we have any concern, in fact, it would be that Maryland’s new 350-hour training requirement to wash and blow-dry hair might gradually ossify into a barrier to entry against whoever comes along to disrupt blowout salons. Today’s insurgent is tomorrow’s incumbent. That’s why Maryland, and all states that want to promote a dynamic, flexible economy, should constantly review and revise the licensing rules.