The man accused of causing a July explosion at a Hartford metal manufacturing plant appeared in court for the first time, with his attorney arguing the criminal complaint lacks definitive proof of his client's involvement.Darrel l Kulas faces four felony counts in connection with an explosion at Signicast Metal Manufacturing that injured three people. If convicted, he could face 42 years and six months in prison and fines of up to $100,000. Christopher Carson, Kulas' attorney, said the charges against his client are not supported by concrete evidence."This is a very unfortunate workplace accident," he said. "Everything in the complaint is suggested. There is no certain causation. There are just hints that maybe he was involved."Carson pointed to the language used in the criminal complaint itself as evidence of the case's weakness.Watch: Felony charges filed against Hartford man who spent three weeks in coma after Signicast blast Felony charges filed against Hartford man who spent three weeks in coma after Signicast blast"I see a lot of 'might have caused, possibly caused, or could have caused' in this complaint, actually alleged," Carson said.The criminal complaint, filed by the Washington County District Attorney's office with investigation details shared by the Hartford Police Department and Wisconsin Department of Justice, Division of Criminal Investigations, accuses Kulas of being under the influence of drugs at the time of the explosion. Police said he was seen slumped over in his car, sleeping before his shift, and stumbling around before an industrial pot containing hot metal burst into flames. Despite the charges, Carson said his client is determined to fight and maintains his innocence."I can tell you he's very emphatic about answering these charges, passionately convinced and plausibly arguing to me facts of his innocence," Carson said. "He wants to answer these concerns."According to the complaint, the State Fire Marshal investigation determined the explosion originated near furnace #1 in the northeast corner of MOD 4, but classified the cause as "undetermined." DCI agents noted that a lack of expertise in metallurgy and industrial melting processes limited the investigation.Investigators identified several contributing factors, including the use of a new and unfamiliar alloy, possible overheating of the furnace, and the possible improper use of an "Argonne drip" a liquid used to introduce liquid metal to molten metal which could cause a violent reaction.Kulas' family launched a GoFundMe on his behalf following the explosion, describing him as a cancer survivor who needed help paying medical bills. The family said he was in a medically induced coma for three weeks after the explosion.Signicast declined to comment when contacted about employee safety and any improvements made since the explosion.Kulas is next scheduled to appear in court for a preliminary hearing on April 8.Washington County Reporter Marcus Aarsvold first reported that Hartford police were investigating an employee back in July.This story was reported on-air by a journalist and has been converted to this platform with the assistance of AI. Our editorial team verifies all reporting on all platforms for fairness and accuracy.Its about time to watch on your time. Stream local news and weather 24/7 by searching for TMJ4 on your device.Available for download on Roku, Apple TV, Amazon Fire TV, and more.Report a typo or error // Submit a news tip ...read more read less