BOSTON (AP) — A Massachusetts man has been ordered held on $200,000 bail on explosive charges in connection to an apartment blast.

Police say a home explosion in Boston was caused by 28-year-old Tomas Mikula experimenting with chemicals. He was arraigned Monday in his bed at Massachusetts General Hospital on explosive charges and possession of a high capacity firearm, and pleaded not guilty.

Police Commissioner William Evans says Mikula was tinkering with chemicals in his East Boston apartment Sunday when they "blew up in his face."

The explosion blew out windows in the second-floor apartment and forced a building evacuation.

Mikula was hospitalized with second-degree burns and is in stable condition.

Evans says weapons and live ammunition were found in the home, but police do not believe the explosion is linked to terrorism.

Mikula's lawyer, Arthur Sabo, sought bail of $1,000.