The T5 Grayslake Chicago IV Campus Facts

Partial and Contested Facts

Little is known about the design and construction of the buildings, and in particular what environmental safeguards are planned. All of the following statements of fact are from the Village of Grayslake FAQ and public statements from Grayslake officials.

• "the data centers that will be built here ...will not result in overall impacts greater than typical light industrial/warehouse/logistics uses that are present in the Peterson Road corridor"

  • Comment: According to Village of Grayslake Zoning Ordinance, Chapter 17: "LIMITED INDUSTRIAL (LI): This industrial zone is established to provide areas for industrial, office, and administrative uses, having few, if any, adverse effects on neighboring properties."

    Data centers typically have diesel backup generator capacity capable of supplying the entire electrical load requirements of the campus, which means there will be enough diesel generators onsite to deliver at least 1.2 GW. At very least, the backup generators need to be tested periodically. 48 hours of testing diesel generators capable of backing up even only 1 GW of electricity will produce a significant amount of particulate air pollution. Residents near such generators frequently report seeing falling soot and black smoke during generator testing or grid-demand events, which stains property and leaves a tangible residue. Neighbors also complain of strong diesel fumes that cause immediate physical symptoms, including severe nose and throat irritation, coughing, and headaches.

    Hyperscale data centers also require Battery Energy Storage Sytems (BESS), lithium backup batteries capable of handling small fluctuations in electrical supply. BESS systems have to be online in fractions of a second when a fluctuation or outage is detected and those handle the load until the diesel generators can start up. With at least 1 GW of battery storage, there is potential for a significant thermal runaway event, a situation in which a battery overheats and causes a lithium fire that creates its own oxygen and can't be put out with water, so it must be allowed to burn. The BESS alone will require enhanced HAZMAT response to contain chemical fires of this scale, to say nothing of the potential environmental pollution a lithium fire will cause. In January 2025 in Moss Landing, CA, a fire broke out in Vistra's 300 MW BESS plant. Firefighters used a "monitor and contain" approach and allowed the fire to burn itself out. The police issued evacuation orders and closed two nearby roads and a highway, and the local school district closed all schools for a day.

    The village FAQ says "very little village costs will be incurred"for municipal services, which is true, because HAZMAT fires are handled by a regional agency (MABAS), so firefighting training and equipment for large-scale BESS fires will be borne by the entire area, not just Grayslake.

• "Closed loop water [cooling] system with minimal water usage".

  • Comment: Closed loop can encompass a number of designs and those have potential environmental and water use implications. How is heat rejected from the site — to air, or to evaporation? What is the annual evaporative consumption, and what is the peak-day rate? How often does the system need to be drained, and where will the drained water go? What additives will be used? What measures will be implemented to contain contaminated runoff?

• Water usage: No more than 50,000 gallons per day.

  • Comment: This is likely true. The village FAQ says will be for "breakrooms/restrooms", and seens consistent with a campus with 1000 employees. A 60 MW data center building would likely require 15-30,000 gallons to fill its closed loop system, but this would be a one-time fill, and buildings would likely be brought online one at a time. So it is likely that water usage will not be an issue with Chicago IV if the system is truly closed loop.

• Backup diesel generators won't run outside of 48 hours of testing.

  • Comment: It is true that there are statutory limits on how much and how often a diesel backup system can be tested. But does the VIllage honestly believe that T5 would install diesel backup generator capacity without ever intending to use it outside of testing? In times of shortage, PJM asks customers who are capable of generating electricty to generate their own. Data centers cannot tolerate power outages, so the diesel generators will run whenever there is an insufficient supply of electricity to Chicago IV for more than a few seconds..

• "it is currently estimated that between 1200 and 1600 jobs will be created."

  • Comment: Actual typical on-site employment for other hyperscale data centers is 20 to 40 on-site workers per 100 MW. In this case, it would more likely be 240-480 on-site workers for the full 1.2GW buildout.

• "It is expected that noise off the campus will be at or below the applicable state standards."

  • Comment: While possibly true of audible sound, there are no state standards for infrasound, which is sound below the 20 Hz level of human hearing,. Infrasound is known to have detrimental health effects on humans and wildlife. High-intensity laboratory and field models show that extreme infrasound exposure can induce oxidative stress, cellular and neuronal apoptosis (programmed cell death), and mitochondrial dysfunction in living organisms. Infrasound can travel easily over long distances and through physical obstacles, interacting with buildings, geological features, or ground structures to create secondary mechanical tremors that affect local living conditions. Because it is inaudible to humans, high levels of infrasound can occur without detection. It can cause symptoms like nausea, dizziness, physical sensations of vibration, ear pressure, fatigue, sleep disruption, and psychological distress or unease.

• "facility equipment is to be spring mounted so there are no anticipated off-site vibrations."

  • Comment: Infrasound is caused by low-frequency pressure fluctuations and mechanical vibrations generated by blade rotation speed, aerodynamic turbulence, and structural resonance. Spings address structural resonance but do not address the full problem.

• "Grayslake residents will pay nothing for the infrastructure to supply electricity to the data center"

  • Comment: ComEd is a regulated monopoly. The Illinois Commerce Commission (ICC) sets the rates that ComEd can charge its customers, and those rates are designed to recover the costs of infrastructure investments, including those made to support large-scale data centers like T5 Chicago IV. Therefore, while Grayslake residents may not see a direct line item on their bills for the data center's electricity supply, they will ultimately bear the cost through higher utility rates.

For a discussion of general hyperscale data center myths, see this flyer.

The Lawsuit

A lawsuit was filed on July 31, 2026, in the Lake County Circuit Court seeking to block and invalidate approvals for the massive 472-acre T5 @ Chicago IV data center campus planned in Grayslake, Illinois.The lawsuit was filed by a group called the Preservation of Community Well-Being Collective LLC along with nine local Lake County residents, naming the Village of Grayslake, developer T5 Data Centers, and landowner Alter Asset Management as defendants.

Key Claims in the Lawsuit

Zoning Issues: The complaint alleges that Grayslake approved the project despite the village's zoning code having no specific category or allowance for data centers.

Open Meetings Act Violations: Plaintiffs claim village officials violated the Illinois Open Meetings Act by conducting deliberations, closed sessions, and negotiations regarding the development outside public view.

Due Process Concerns: The suit argues that the approvals granted between September 2024 and May 2025 lacked adequate public disclosure and process, noting that key zoning items moved through public hearings rapidly with little room for public comment.

Project Scope: The proposed campus in the Cornerstone business park is slated to exceed 10 million square feet and draw roughly 1.55 gigawatts of power, making it a development of unprecedented scale for Lake County, far exceeding its zoning as "light industrial".