Most major American cities do not smell good. Walking through the streets of New York can bring encounters with the penetrating funk of urine, sweat, and last week's pizza. In downtown Los Angeles, the smell of catalytic converter exhaust and hot asphalt is a daily reality.

Big cities are not alone in this regard. Googling “Why does [city name] smell” for most urban areas results in endless forum posts from city dwellers asking why their neighborhood smells like “something dead” (Columbus, Ohio), or why summer in the city means the smell of vomit and semen (Washington, D.C.), or why getting the perfect view of Milwaukee, Wisconsin from the Hoan Bridge involves the overpowering stench of “fish and ash.”

For now, most of these city smells are not strong enough to repel citizens (and weak enough to earn cheeky nicknames: Tacoma, Washington’s stench of rotten eggs has been dubbed the “Aroma of Tacoma,” and has its own Wikipedia page). But jokes aside, President Donald Trump’s aggressive deregulation agenda could make America’s stench much worse — and more toxic.

It is important to note that the state of American health and environmental regulation prior to Trump was already really, really bad. The Poison Papers, a collection of documents released last year by The Bioscience Resource Project and The Center for Media and Democracy, detailed everything from Environmental Protection Agency testing malpractice to the government’s attempt to fight weeds by spraying them with Agent Orange. But while the use of strong chemicals in an industrial context has been in public consciousness since the late '70s, one industry has since emerged as particularly exploitative of the government’s under-regulation: cosmetics, with fragrances as the main culprit.

The cosmetic industry’s ability to exploit the country’s under-regulation stems mostly from a loophole in the 1973 Fair Packaging and Labeling Act. This bill was enacted to ensure companies were accurately listing ingredients so consumers could be more informed about what, exactly, they were buying. However, buried in the text of the bill is a specific clause for flavor and fragrance — elements the Food and Drug Administration claimed were most likely to be “trade secrets.” This meant that flavor and fragrance were not subject to the same application process as other trade secret ingredients, which allowed them to be listed on product labels as an additional “fragrance” or “flavor” instead of as their actual components.

Since the bill’s passage, fragrance manufacturers have used this stipulation to add largely untested chemicals into cleaning supplies, perfumes, food, and other everyday products. A 2010 report by the Campaign for Safe Cosmetics and Environmental Working Group found that while 81 percent of listed fragrance chemicals in tested perfumes had been assessed for safety, 66 percent of unlisted chemicals discovered to be present in the tested perfumes had not. This means that the average perfume, which has approximately 43 total ingredients, has about 12 completely untested components, with some perfumes having as many as 16.

Many of these unlisted fragrance chemicals have been shown to have a dramatic impact on human life. In 2014, a Columbia University study found that both di-n-butyl phthalate (DnBP) and di-isobutyl phthalate (DiBP), which are added to fragrances to improve solubility, caused a drop in IQ of more than six points in children born to mothers determined through urine samples to have been exposed to the chemicals during pregnancy when compared to children born to mothers without similar exposure. This was after a 2010 report by the University of Washington that found that more than a third of tested products with added fragrance released at least one probable carcinogen as defined by the EPA.

In urban environments, fragrances are often downright impossible to avoid — by design. Chain stores have adopted a practice known as “olfactory branding,” pumping aromas into and outside of retail locations in order to be associated with a scent of their choosing rather than the often sour stench of the urban outdoors (this is one of the reasons why stores like Cinnabon and Lush can be smelled for blocks before the store is actually in sight). Much like perfumes, the contents of these diffused aromas and their lasting effects are generally untested –– “Fierce,” the scent that filled all Abercrombie and Fitch stores until July of last year, contained chemicals known to cause allergic reactions, leading to reports of visitors and employees getting splitting headaches, becoming anxious, and developing red eyes and brittle nails by the end of the workday.

In an urban setting, the aromatic impact of these diffused scents is much more profound. Areas with high population densities are subject to what scientists call the “urban heat island effect,” where cities are on average 1.8 to 5.4°F warmer during the daytime and up to 22°F warmer at night than their rural counterparts. Higher temperatures cause smells to feel more pronounced and travel further, making cities a literal hotbed for scent interaction. As scent use and the scents themselves spread, more people have reactions to them. According to a 2017 study in Preventive Medicine Reports  some 17 percent of people report respiratory difficulties when exposed to fragrances, with around 4 percent also reporting issues like dizziness, fainting, or trouble with memory. With a growing number of stores releasing their “olfactory brand” into the wind, the already pungent urban air has the potential to become a warm, noxious chemical slurry.

It comes as no surprise that these issues of under-regulation are getting worse under Trump. The Food and Drug Administration, the main regulating body in charge of making sure cosmetic companies don’t violate current rules, sent out a mere 265 warning letters to companies it believed had committed serious violations of federal guidelines in the first seven months of 2017. This is the lowest number of warnings sent out since 2008, 30 percent lower than the average over all eight years of Obama’s tenure.

Furthermore, even if the FDA was to change course and begin regulating cosmetics more harshly, their ability to do so would be hampered by a complete lack of data. Current laws do not require cosmetic companies to register with the FDA; companies are also not required to disclose safety data, consumer complaints, manufacturing locations, product names, product ingredients, or ingredient quantity. In fact, if a possible health concern is reported, the FDA must often buy the product themselves before they can conduct an analysis. This approach stands in stark contrast to the E.U. and Canada, which have restricted or outright banned the use of more than 1,300 chemicals in cosmetic products as of 2016. That number in the U.S.? Eleven.

Fortunately, there is some movement when it comes to expanding the FDA’s authority. Rep. Frank Pallone, a Democrat from New Jersey who is expected to be the next House Energy & Commerce chairman, introduced legislation in 2016 to strengthen the FDA and expand their reach when it comes to cosmetics regulation. While this bill stalled out in a GOP House, it has the potential to return following the Democrats’ recent House majority victory. Scott Gottlieb, the current FDA commissioner, is open to the idea, saying he has “long said that... the cosmetics program inside FDA has been under-resourced,” later adding that the agency was “still facing a challenge with... respect to cosmetics, with growing complexity and growing risks."