Two workers at the Baseline Tennis Center expansion site suffered chemical burns Monday at approximately 2 p.m. after a bottle containing a liquid broke and splashed on them.

A crew was excavating and assessing the site of the four tennis courts being added behind the tennis center on Fifth Street Southeast.

The construction worker from Veit Companies, which is handling the excavation of the site, was taken to Hennepin County Medical Center and held overnight for observation, according to Greg Boelke, senior vice president for Veit Companies.

An employee from Liesch Companies, an environmental consulting company, was also injured, said Roger Wegner, project manager of the tennis courts for University capital planning and project management. At press time, it was not known which hospital that worker was taken to.

The land was home to an abandoned building that was demolished approximately two weeks ago.

The building was previously owned by McLaughlin Gormley King Co., a manufacturer of insect repellents and insecticides.

Wegner worked with the Minnesota Pollution Control Agency during other environmental assessments to dispose of materials from the abandoned building and the ground beneath it.

“There were very significant environmental issues, which is why (the building) sat there so long,” Wegner said. “The environmental issues have been a point of discussion since the beginning.”

Craig Moody, director of University health and safety, sent a chemical-spill response team to the site.

“There is always a chance there is going to be some isolated orphan material like this,” he said. “But it’s fairly uncommon for us to run across containers like this at a site.”

The bottle was found while the crew was excavating around a pipe and testing for asbestos.

The Minneapolis Fire Department and the department’s hazardous materials response team, as well as the University chemical-spill response team, cleaned the site.

Wegner said it was too early to know if the project would be halted.

Boelke said the Veit crews would not return to work until they had an all-clear from the University team.

Originally, Wegner said, the tennis courts were to be completed by mid-October.

The courts marked the completion of a long-term project that included the construction of Ridder Arena and the Baseline Tennis Center, said Scott Ellison, associate director of athletics facilities.

Athletics Director Joel Maturi said that without the courts, the University has not been able to host the Big Ten women’s tennis tournament, which changes location annually.

The University must have 12 courts to host the tournament.

Orlyn Miller, director of planning and management for capital planning and projects management, said the tennis courts were paid for by a donation from a tennis boosters club.