A woman who opened a letter bomb was shunned by colleagues who were also hurt in the blast, a court has heard.
Miles Cooper worked as a primary school caretaker
Karen Andrews opened the envelope at the DVLA headquarters in Swansea on 7 February after a spate of similar attacks across the country.
Mrs Andrews told Oxford Crown Court some colleagues blamed her and refused to work with her after the incident.
Miles Cooper, 27, from Cambridge, denies 12 charges related to letter bomb attacks in January and February.
Mr Cooper allegedly sent seven letter bombs, five of which exploded, injuring eight people.
The locations were Abingdon in Oxfordshire, Culham near Abingdon, Birmingham, Folkestone in Kent, Victoria in central London, Wokingham in Berkshire, and Swansea.
Mrs Andrews told the court that, as she opened the envelope, she joked: "Do we think this is suspicious?"
She added: "I was just joking. It was because it was a Jiffy bag and because of what had been on the news."
She opened an envelope inside the original package and saw a bright flash and heard a very loud bang.
Mrs Andrews said she now suffers from post-traumatic stress disorder and permanent tinnitus, and is left with a large scar on her upper chest from stitches.
She told the court: "I've been forced out of my department because some colleagues refuse to work with me.
"One manager even wanted me to apologise to people for what I did that day."
A colleague of Mrs Andrews, Chris Phillips, told the court she had been "playing around" with the envelope.
Forensic scientist Lorna Philp said in court the bombs sent in January had ground down match heads packed into a thin metal tube.
Those sent in February differed by having firework powder inside a thin glass bottle, which fired shards when exploded.
The jury was shown photographs of Mr Cooper's bedroom and garage after police raided the home he shared with his mother Lorraine and sister Sally.
Three further devices were packed up and addressed, and fireworks, matches, party poppers and other bomb-making equipment were seized.
'Things got blurry'
The court also heard from Richard Gorringe, of accountancy firm Vantis in Wokingham, Berkshire, who opened a letter sent to safety camera manufacturer Speed Check.
He said: "I opened the inside envelope but then things got a bit blurry for me.
"When I pulled it out, I assume that's when it exploded and I think I blacked out a bit.
"When I came to, there was a loud ringing in my ears and my vision was a bit blurry."
Mr Gorringe received injuries to his hands which prevented him playing golf for three months.
The case continues.