In Tarquinio v. Johns Hopkins University Applied Physics Lab, the U.S. Court of Appeals for the Fourth Circuit addressed the contours of an employer's obligation to provide accommodations under the Americans with Disabilities Act when an employee fails to meaningfully participate in the interactive process.

The June 25 decision affirms that while the ADA requires employers to engage in good faith with accommodation requests, the duty to accommodate does not arise until the employer has adequate notice of the employee's limitations and the need for accommodation — and that obligation can be extinguished if the employee obstructs the process.

Case Background

The dispute arose after the Johns Hopkins University Applied Physics Laboratory, or APL, which is a federal contractor, implemented a mandatory vaccination policy during the second year of the COVID-19 pandemic.

The policy was consistent with guidance from the Safer Federal Workforce Task Force and applied to all employees, subject to medical and religious exemptions.

Sally Tarquinio, a systems engineer at APL, sought a medical exemption from the vaccine mandate. She asserted that she had a chronic complication from Lyme disease, called Lyme-induced immune dysregulation, which she believed would cause "immune chaos" if she received the COVID-19 vaccine.

In support of her exemption request, Tarquinio submitted a 2012 blood test showing prior Lyme disease, along with a brief form that was signed by her healthcare provider.

The form listed "chronic Lyme Disease [and] Lyme induced immune dysregulation" as the reason for the exemption, but provided no current laboratory results, treatment records or detailed explanation of her functional limitations.

APL reviewed the submission and noted that the Centers for Disease Control and Prevention did not recognize Lyme disease as a contraindication to COVID-19 vaccination.

The laboratory asked Tarquinio for current medical documentation, and requested permission to speak directly with her treating physicians to better understand her condition and the risks associated with vaccination.

Tarquinio refused both requests. She insisted that APL already knew everything about her medical history and accused the laboratory of second-guessing her healthcare providers. She also rejected any authorization for APL to speak with her doctors.

While she proposed alternative measures — such as weekly on-site COVID-19 testing at her own expense and a hybrid work schedule — APL maintained that it could not evaluate those options without sufficient medical information to establish that she was entitled to an exemption in the first place.

Because Tarquinio did not comply with the vaccination requirement or obtain a formal exemption, APL terminated her for noncompliance with the mandate.

She subsequently filed suit in March 2023 in the U.S. District Court for the District of Maryland, alleging that APL violated the ADA by failing to accommodate her disability, wrongfully terminating her employment based on that disability, and conducting an unlawful medical inquiry or examination.

The district court granted summary judgment for APL in April 2024. It found that Tarquinio had not provided adequate documentation to support her accommodation request, and that she had actively blocked the interactive process by refusing reasonable requests for information.

Thus, without sufficient medical details, APL could not determine whether she had a qualifying limitation that would necessitate an accommodation. Tarquinio appealed.

Fourth Circuit Ruling

On review, the Fourth Circuit unanimously affirmed the district court's decision. Writing for the panel, Chief U.S. Circuit Judge Albert Diaz emphasized that an employer's duty to provide reasonable accommodation under the ADA only arises when the employer has actual knowledge of both the disability and the specific limitations it imposes on the employee's ability to perform essential job functions.

The court explained that the ADA's interactive process is intended to be a collaborative dialogue between the employer and the employee to identify limitations and explore possible accommodations.

However, that process is a means to an end, not an independent obligation. If an employee refuses to provide the employer with information that is necessary to assess their needs, the process cannot proceed, and the employer's duty to accommodate may never arise.

The Fourth Circuit stressed that employers are entitled to request reasonable medical documentation to verify both the existence of the disability and the need for accommodation, particularly when a disability and its limitations are not obvious.

This documentation should be current, relevant and sufficient to explain how the disability limits the employee's work, and why the requested accommodation is necessary.

In this case, Tarquinio provided only outdated records and a conclusory note from her provider. Her refusal to authorize communication with her doctors or provide additional details left APL without the ability to verify her claims or evaluate her proposed accommodations.

The Fourth Circuit also rejected Tarquinio's argument that APL had second-guessed her medical providers. Instead, it framed APL's requests for updated documentation and provider contact as legitimate steps in the interactive process, especially since her claimed limitation — a potential adverse reaction to a vaccine — was not self-evident, nor recognized in public health guidance as a contraindication.

The court concluded that, without cooperation from Tarquinio, APL had no legal duty to implement her requested accommodations.

In addition to the failure-to-accommodate claim, the Fourth Circuit also affirmed dismissal of Tarquinio's wrongful termination claim, holding that termination for failure to comply with a lawful vaccination policy — absent evidence of discrimination — does not violate the ADA.

Likewise, the court rejected Tarquinio's unlawful medical inquiry claim, finding that APL's requests for documentation were job-related and consistent with business necessity under the statute.

Key Takeaways

The Fourth Circuit's decision carries significant implications for both employers and employees in relation to navigating the ADA accommodation process.

For employers, the ruling confirms that they can require up-to-date and relevant medical documentation before granting accommodations, particularly when the disability or limitation is not obvious.

Employers are not required to accept vague or outdated information at face value. They are also entitled to verification, including the ability to consult with medical providers, provided that the request is reasonable and related to the accommodation assessment.

The decision also underscores that while employers must engage in good faith in the interactive process, they will not be held liable if an employee's refusal to cooperate causes the process to break down.

For employees, the decision is a cautionary reminder that asserting a disability is not enough to trigger accommodation rights under the ADA. Employees must provide sufficient and current medical evidence to substantiate both their condition and its impact on their job performance.

Refusing to cooperate with an employer's reasonable requests for information — including by declining to authorize communication with medical providers — can jeopardize not only the accommodation request, but also potential legal remedies if the employment relationship ends.

Specificity, transparency and active engagement are critical to protecting ADA rights.

Ultimately, Tarquinio v. Johns Hopkins University Applied Physics Lab reaffirms that the ADA accommodation process is a shared responsibility. It requires mutual participation, timely and adequate exchange of information, and a willingness on both sides to explore reasonable solutions.

Conclusion

The Fourth Circuit's decision draws a clear boundary: When an employee obstructs the process, the employer's legal duty to accommodate may never come into play.

By clarifying the interplay between employee cooperation and employer obligations, the ruling strengthens guidance for ADA compliance in workplaces across the Fourth Circuit and beyond, particularly in contexts involving complex or disputed medical conditions and public health policies.

It serves as a reminder that the ADA is not a one-way street — its protections depend on open communication, reasonable verification and a cooperative approach from both parties.

The opinions expressed are those of the author(s) and do not necessarily reflect the views of their employer, its clients, or Portfolio Media Inc., or any of its or their respective affiliates. This article is for general information purposes and is not intended to be and should not be taken as legal advice.