BOSTON (CBS) — The East Boston man who was seriously burned after an explosion in his house on Sunday was arraigned from his hospital bed on multiple charges related to making a bomb.

Tomas Mikula, 28, of Webster Street pleaded not guilty to all of the charges and will be held on $200,000 cash bail.

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Police said Mikula was tinkering with bomb-making materials when the explosion occurred around 12:40 a.m. He was transported to Massachusetts General Hospital with second-degree burns.

Tomas Mikula is arraigned from his hospital bed (WBZ-TV)

The explosion created a hole in the floor, blew out some walls, and caused debris to go flying across the street. When police searched the apartment, they found materials to make a homemade explosive device, including PVC tubing and chemicals. Two handguns, a rifle, and over 100 rounds of live ammunition were also found in the house.

Four people were in other apartments of the multi-family home when the explosion occurred.

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Boston Firefighters respond to a home explosion on Webster Street early Sunday morning (WBZ-TV)

Mikula was charged with unlawful possession of explosives, unlawful possession of an incendiary device, willful ignition/discharge of a destructive or incendiary device, unlawful possession of a firearm (handgun), unlawful possession of a firearm (rifle), unlawful possession of ammunition, and unlawful possession of a high capacity firearm.

If Mikula were to post bail, he will be ordered to surrender his passport, stay away from his house at 88 Webster Street while being confined to another home, and wear a GPS monitoring device.

Prosecutors also said Mikula had a criminal history, including credit card and identity theft charges, theft charges, and a 2009 firearm conviction.

Mayor Marty Walsh said Sunday Mikula did not appear to have any ties to terrorism. The motive is under investigation.

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Mikula is scheduled to return to court for a probable cause hearing on August 6.