Prosecutor Gunilla Oehlin said small traces of TNT were detected on the shaving cream can, but there was no explanation for how it got there and there was no reason to suspect the two men of any crime, TT said.
The two men, born in 1955 and 1964, had been working as welders for several weeks on one of three reactors at the Oskarshamn plant in southern Sweden.
They were arrested on May 21 after a routine security control at the entrance to the plant detected traces of highly explosive material on a plastic bag containing toiletry items that one of the men was carrying.
The two men were released from custody after one day, after raids in their homes turned up nothing.
“It was necessary to carry out the investigation this way and arrest the men so they could be questioned,” police spokesman Sven-Erik Karlsson said, TT reported.
At the time of the incident, police said the highly explosive material detected was TATP, which is relatively easy to make and has surfaced in a number of recent terrorism investigations, including bombings in the Middle East and the London bombings in July 2005.
Police said on Monday however that the plant’s equipment had detected TNT and not TATP, but had no further explanation for why it had been detected.
A bomb squad called in to the plant on the day of the incident had blown up the plastic bag and the shaving cream can.
Forensic tests later carried out on the blown up material showed traces of the bomb squad’s explosives, but no traces of TNT.
Police were unable to explain where the TNT could have come from.
The false alarm cost OKG, the company that runs the plant, some 100 million kronor ($16.8 million), according to tabloid Expressen.