Todd Dwight Wheeler Jr., 28, of Glen Burnie, 40 miles northeast of Washington and 10 miles south of Baltimore, was held at an Annapolis detention center, officials said.
He was charged with two counts of making explosives, two counts of possessing explosive materials and one count of reckless endangerment, the officials said. Federal charges are pending, they said.
Wheeler, whose home was found to have more than 100 pounds of bomb-making acids, fuels, oxidizers and explosives precursors, "had the capability of causing destruction and terror in our county," Anne Arundel County Executive Laura Neuman told reporters.
Police said they didn't know what Wheeler's plans for the explosives were because he's refusing to cooperate.
But "what is clear is that these materials were capable of maiming, killing or injuring human beings," Fire Chief Michael Cox said at the news conference.
Officials, including from the Bureau of Alcohol, Tobacco, Firearms and Explosives, displayed evidence including glass jars labeled "ammonium chloride," "potassium chlorate" and "sulfur," the Baltimore Sun reported.
They also found igniters, detonators, guns, knives and how-to manuals in his home, they said. The books include titles such as "Booby Traps," "Deadly Brew," "Highly Explosive Pyrotechnic Compositions" and "The Poor Man's James Bond," they said.
If the bombs had exploded, the blast would have had a radius of more than 150 feet -- big enough to "have taken out the house and the surrounding houses," Fire Capt. Robert Howarth said in remarks quoted by NBC News.
Wheeler was arrested New Year's Day after police were called to his address by a relative concerned he might be suicidal, police said in a statement. They described the investigation Tuesday.
When Wheeler was apprehended, he appeared to have injuries consistent with those caused by a chemical reaction, the statement said.
Wheeler is to have a preliminary hearing in the county District Court in Annapolis Jan. 29.
It was not immediately clear if Wheeler had an attorney.