
Earlier this month, the Maryland Appellate Court issued a controversial ruling in Candace McCarthy v. Board of Commissioners for Frederick County, Maryland, holding that Frederick County is immune from a negligence claim stemming from mold exposure in the historic John Hanson House.
The decision, issued on the same day Maryland’s new mold exposure law took effect, has drawn sharp criticism in both legal and environmental communities, many arguing that the court applied an outdated legal framework that fails to address modern environmental health risks in a historically preserved building.
“The King Can Do No Wrong”
The doctrine of sovereign immunity originates in English common law, where the Crown could not be sued in its own courts without its consent. This principle, rex non potest peccare (the king can do no wrong), was imported into American legal doctrine and became embedded in U.S. jurisprudence at both the federal and state levels.
A Historic Home, A Modern Health Hazard
The John Hanson House, named after the first person to serve a full term as President of the United States in Congress Assembled under the Articles of Confederation (1781–1782), is part of Frederick County’s courthouse complex. The County acquired the 4.3 acre property in 1975 with plans to renovate the 1700s structure for commercial and office use. Since 1984, the Office of the Public Defender, a state agency, has leased space in the building.
In 2018, Public Defender employee Candace McCarthy complained of mold in the building’s basement. Testing confirmed its presence. McCarthy alleges that exposure to mold in the John Hanson House contributed to her development of an autoimmune disease. She brought a negligence claim against the County, asserting its failure to maintain safe conditions in the leased space.
The Court: Governmental Immunity Prevails
The Maryland Appellate Court affirmed the dismissal of McCarthy’s lawsuit on the grounds of governmental immunity. Local governments, counties, municipalities, and other subdivisions are not “sovereigns” in the constitutional sense, but they still enjoy forms of immunity under state laws, and in this instance under Maryland law.
Citing longstanding Maryland law, the court concluded that Frederick County’s maintenance of the John Hanson House qualified as a “governmental function,” not a “proprietary” one, thus shielding the County from liability.
In its reasoning, the court applied the State’s four factor test to determine whether a government action is “governmental”: (1) Authorized by legislative mandate; (2) Performed solely for public benefit; (3) Without private profit or emolument; and, (4) Designed to promote public health or welfare.
Although the County collected rent from the Public Defender, the court deemed this reimbursement for operating costs, not profit, emphasizing that the building’s integration into the courthouse complex affirmed its governmental nature. The failed maintenance of the John Hanson House, the court concluded, was thus immune from tort liability.
A Faulty Framework for the 21st Century
That conclusion might make sense in the abstract, but in the context of this case, it reflects a profound legal blind spot. Mold in historic structures, particularly Colonial buildings like the John Hanson House, is a foreseeable risk that arises from known construction vulnerabilities. These include the use of porous materials like wood, horsehair plaster, and brick, along with the absence of vapor barriers, waterproofing, or modern ventilation systems.
This isn’t an abstract or rare concern. Mold is common in historic buildings reused for modern occupancy in Maryland (.. not to mention privately owned buildings). The risk is exacerbated in structures with subterranean or poorly ventilated areas, like the basement of the John Hanson House, where moisture accumulates and fungi thrive.
That Frederick County failed to prevent or remediate mold in a structure it actively leased for office use after actual notice of the indoor air quality issue should raise serious concerns. That the law prevents a harmed individual from seeking a remedy only underscores how governmental immunity can serve as a blunt instrument that thwarts justice and the safety of the governed.
A Legal Decision Issued the Same Day as a New Mold Law?
The timing of the court’s ruling only highlights the gap between emerging environmental health realities and ossified legal doctrine. On the same day the appellate decision was published, Maryland’s new mold law, 2025 Senate Bill 856, took effect. The statute, for the first time, regulates mold in rental properties. While it doesn’t apply retroactively, the legislation represents the state’s growing recognition that mold exposure is a serious public health risk, deserving for the first time, state regulation; but how will the law be implemented for public buildings?
Maryland has expanded the role of government to now include the regulation of mold in rental properties, but this mold claim is rebuffed because the County landlord is pursuing a government function. But for Candace McCarthy, that regulation comes too late. Moreover, there is some irony there?
Preservation or Public Health? Why Not Both?
Historic preservation is a commendable public policy goal. The adaptive reuse of heritage buildings, including those with Revolutionary era roots like the John Hanson House, plays a vital role in community identity and sustainability.
But preservation must not come at the cost of human health. It is unacceptable to restore and repurpose buildings from the 1700s without modernizing them to meet 21st century indoor air quality standards. People today spend nearly 90% of their time indoors, according to the EPA. Indoor air, often more polluted than outdoor air, is a frontline environmental health concern. Biological contaminants like mold can cause severe, even lifelong, respiratory and immune system conditions as alleged here.
If we are to responsibly preserve the past, we must ensure those buildings do not harm the people living and working in them today.
A Legal System Behind the Times
The real issue is not with the court’s logic, within the confines of current Maryland law, the ruling arguably got it right. Rather, the problem lies with the doctrine of governmental immunity itself. While total immunity is conferred on the State of Maryland and its agencies, counties and municipalities receive limited immunity when acting in a “governmental” capacity. That distinction, however, is increasingly unworkable in the modern world.
In this case, the County acted not as a sovereign authority, but as a landlord leasing office space in a commercial arrangement. Yet, because the building was nominally part of a state courthouse grounds and complex, the County was deemed immune from responsibility for known, preventable environmental hazards.
It is a fundamental precept of our constitutional order that for every wrong, there is a remedy. Sovereign immunity erodes that guarantee.
Conclusion: Modernize Government Immunity
The McCarthy case illustrates the urgent need for Maryland and other states to modernize doctrines of governmental immunity, particularly when public health is at stake. As science based professionals and legal commentators have noted, this decision applies an 18th century legal shield to a 21st century environmental issue. That’s not just injudicious, it’s dangerous.
Critics argue that the original rationale, “the King can do no wrong,” is an anachronism in a modern constitutional democracy. The government is not a monarch, and the people are not subjects. Justice John Paul Stevens once wrote that absolute immunity “runs counter to democratic principles of accountability.”
It is time to recalibrate the balance between governmental protections and individual rights in the face of evolving environmental hazards. McCarthy’s case is not just about mold. We are reminded of children injured by lead based paint in government housing who have been denied justice.
This case is about whether our legal system is equipped to respond to the real world impacts of outdated building practices and whether our governments, local, state, and federal, will be held accountable when they fail to protect the people they serve.
Historic buildings deserve preservation. But so do the people who work in them. The bottom line is that limited immunity should protect governance, not shield harm.
You can read the full decision here:
Candace McCarthy v. Board of Commissioners for Frederick County, Maryland