HOBART, Ind. — Police found what they believe was a methamphetamine lab inside a White Castle restaurant in northwest Indiana Friday, according to WGN.

Officers were called to the White Castle at 7996 W. Ridge Rd. in Hobart, Ind., about 10:50 a.m. Friday for a report of a suspicious person, according to the Hobart Police Department.

Police found a man with a “suspected one pot” meth lab, the department said in a statement. A one-pot meth lab is a bottle filled with chemicals. The lab is dangerous because there is often only a thin layer of plastic covering the chemicals, police have said.

Four officers were treated for exposure to chemicals. Indiana State Police were called to safely contain the lab; officers took one man into custody.

A White Castle spokesman said the restaurant reopened by 6 p.m. Friday following an inspection by the local board of health. There were no violations, the spokesman said.

The company’s vice president, Jamie Richardson, released the following statement:

“We are proud of our White Castle team members who alerted local authorities about a suspicious customer, and thankful for the Hobart Police Department’s rapid response. We are grateful to be part of a community where everyone looks out for one another, and works together to keep our neighborhoods safe.”