The report, by consulting engineer Terracon Inc., said the South Side site had mercury, arsenic and other contaminants in its soil. The city said it had ordered soil in areas that had higher than acceptable mercury and other contaminant levels to be removed and properly disposed of, and that the site would have been safe to begin construction on Dec. 4.

"We have temporarily paused construction on the site pending Illinois Environmental Protection Agency review of the environmental study," a statement from Pritzker said. On Dec. 5, the head of the state agency said the project will not move forward without further remediation measures.

Johnson proposed in September to move migrants, who have been arriving in Chicago for the last two years, from police stations where many have been sleeping to "winterized base camps." Private security firm GardaWorld Federal Services and its subsidiary, Aegis Defense Services, won a $29-million city contract to provide that temporary housing, "on an as-needed basis” for the migrants, according to city procurement records.

However, even before Terracon's environmental review for the city was released, the project faced a labor challenge. On Nov. 30, Iron Workers Local 1 filed a notice of intention to picket the site on 38th and California Streets due to Gardaworld’s failure to hire union iron workers.

GardaWorld and Aegis are not union contractors, although their security personnel are members of a security services union. Other union workers on the site would almost assuredly honor the ironworkers' picket, lay down their tools and halt any potential construction on the site. All fencing and metal framing for structures such as those planned for the South Side site are required to be performed by union workers in most cases using Chicago's normal construction procurement process.

Officials from Local 1 did not immediately return queries about the potential picket that was filed. 

"On Thursday, November 30, Iron Workers Union Local 1 filed a notice of intention to picket the Brighton Park migrant camp site on Friday, December 1, which is currently under construction, due to the contractor’s failure to hire certified union iron workers," Local President John Gardiner said in a statement to several Chicago media outlets. "After receiving a call from the governor’s office last night, .... the [union] agreed to a 24-hour pause on our picket to allow for negotiations. We paused our picket for 24 hours out of courtesy to the governor’s office. We met virtually this morning with multiple, high-level officials, and will continue to talk throughout the day."

Johnson's office cited a statewide emergency declared by Pritzker in September 2022 related to the migrant crisis as the predicate for both the project speed and for using a firm such as GardaWorld that falls outside of the normal Chicago construction procurement process and federal prevailing wage laws.

"Governor Pritzker’s migrant-related disaster proclamation, which remains in effect, activated the Illinois Emergency Management Act," Johnson's office said in a statement. It allows for the use of temporary emergency housing, said the statement, and "the Governor, the director and the political subdivisions of the State are directed to utilize the services, equipment, supplies and facilities of existing departments, offices and agencies of the State and of the political subdivisions of this State, to the maximum extent practicable," and all state departments must cooperate.

In September 2022 Pritzker said, in declaring the state of emergency, that "the state of Illinois is doing everything in its power to support local jurisdictions to help ensure that the right tools and supports are in place as we move forward with this humanitarian response."

Illinois also provided $65 million in state funds for a "winterized shelter" in Chicago in a Pritzker executive order on Nov. 16. 

Associated General Contractors of Chicago officials had no comment on a security firm being hired for the work and not a licensed and bonded general contractor. 

“While limited information is available about this structure being built, Associated Builders and Contractors believes projects should be built through fair and open competition with transparent rules that create the conditions to add the best value for all involved," said Alicia Martin, president of the Associated Builders and Contractors of Illinois.

Ronnie Reese, press secretary for Johnson, added that the city "is scrupulously adhering to all functional standards of health and safety that are embodied" in the Chicago municipal code.

On Dec. 5 IEPA Director John J. Kim said the migrant shelter project would not continue in any form without further remediation efforts.  

"IEPA would not approve the proposed Brighton Park site for residential use, based on our regulatory standards for remediation of contaminated properties," Kim said. "The well-being of residents and workers at the site is our highest priority, and current and planned site conditions do not adequately reduce risks of human exposure to known and potential environmental conditions."

This article was updated December 6 to include the statement from IEPA.