Illinois Governor J.B. Pritzker has halted construction activities on a base camp for migrants in Chicago's Brighton Park neighborhood pending a review of an environmental report released last week. The governor's office stated that the pause is necessary to allow Gov. Pritzker to thoroughly examine the report and engage in discussions with the Illinois Environmental Protection Agency, which are expected to occur on Monday.

The release of an 800-page environmental assessment report by the city of Chicago late Friday revealed the presence of soil contamination, specifically mercury and other compounds, at the Brighton Park site. Notably, the mercury levels found in the soil exceeded environmental limits. In response, the city has already taken action by removing and properly disposing of the contaminated soil.

The location, situated near West 38th Street and South California Avenue, was intended to provide temporary housing for up to 2,000 migrants as part of the city's efforts to address the growing number of individuals seeking shelter in locations such as airports and police stations as winter approaches.

However, Brighton Park residents and environmental advocates have voiced their opposition to the site due to concerns about its location and potential environmental hazards. Mayor Brandon Johnson's office released a statement acknowledging the presence of high levels of semi-volatile compounds in another area of the site, noting that steps will be taken to address this issue as well.

The statement from Mayor Johnson's office assured that the removal of the contaminated soil and the placement of an engineered barrier across the site have made the area safe for temporary residential use. The barrier, consisting of crushed clean stone with a minimum thickness of 6 inches, will be regularly inspected to maintain its integrity.

Construction efforts at the site had progressed rapidly over the past week after the city awarded a $29 million contract to GardaWorld for the construction of temporary structures. Tent-like structures have already been erected on the site, and heavy equipment, including generators and lumber-laden semis, has been seen on the premises.

NBC 5 Investigates made repeated attempts to obtain an update from Mayor Johnson on the site's progress but received no response. The news outlet also highlighted concerns from Ald. Julia Ramirez, representing the ward encompassing the site, who voiced frustration over what she perceived as inadequate communication and transparency from the city in handling the environmental issues, while noting that remediation efforts had been carried out.

Mayor Johnson, however, defended his administration's approach, rejecting claims of a lack of transparency during a news conference. He emphasized that the assessment of contaminants at the site was ongoing and assured that the full report would be provided by the end of the week.

Records obtained by NBC 5 Investigates revealed that the site had previously been used as a zinc smelter and was part of a railyard.

As the pause in construction persists, it remains to be seen how the environmental concerns will be addressed and whether the base camp for migrants will proceed as planned. The governor's review of the report and subsequent discussions with the Illinois Environmental Protection Agency will likely shed light on the next steps to be taken regarding the Brighton Park site.