Johnnie Walker producer Diageo could potentially face a lawsuit over fungus caused by “angel share vapors” at one of its Scotland whisky facilities.

Following a ruling by a Court of Session judge on June 30, Bonnybridge homeowners Thomas and Gail Chalmers are now permitted to sue the spirits giant for allegedly damaging and devaluing their home, according to The Drinks Business. The Scottish residents claim that the black stains on their home were caused by the ethanol released from a Diageo whisky warehouse located about 350 meters (1,148 feet) from their property.

The “angel’s share,” or the vapor that evaporates from whiskey while it’s matured in barrels, can cause a black, velvety fungus called baudoinia to form, which can coat nearby surfaces. The fungus, often referred to as distillery fungus, is commonly found on structures near mass-market spirit productions.

The Chalmers’ legal case was first introduced in 2017 after the couple requested £40,000 ($50,967 USD) in damages. They cited stains on their house’s exterior and outdoor furniture, which they claimed needed to be power-washed and bleached frequently.

Diageo disputed the claim later that year, per The Spirits Business. But last week, overseeing judge Lady Carmichael ruled that the couple can now proceed with their suit. In a July 6 email to VinePair, the spirits company reiterated its opposition to the couple’s allegations.

“We are disappointed in the court’s decision and are considering our options for appeal as we strongly dispute the claims made against us,” a Diageo representative stated.

This isn’t the first time this year that homeowners have expressed continued concern about distillery-related property damage. In March 2023, Tennessee residents voiced their complaints after “whiskey fungus” allegedly stained properties near a Jack Daniel’s barrelhouse. A local judge ordered a temporary pause on the company’s warehouse expansion after a Lincoln County resident filed a lawsuit against the county’s zoning department.

Distillery fungus typically forms in high-humidity climates with regular rainfall, according to the Indiana State Department of Health. There’s insufficient evidence that it causes direct health issues in humans, but experts recommend wearing protective gear while removing the fungus. For distillers, though, the fungus is difficult to prevent and even harder to completely destroy.

This story is a part of VP Pro, our free content platform and newsletter for the drinks industry, covering wine, beer, and liquor — and beyond. Sign up for VP Pro now!