An employee for Blick's Phosphate Conversion, LLC, succumbed to his injuries Wednesday after being exposed to Ammonia at Simplot's Don Plant Saturday.
Power County Sheriff's Deputies along with the Pocatello Fire Department were called to the scene Saturday afternoon.
When crews arrived, they found Derrick E. Martinez, 23, unconscious in a mobile testing trailer. Investigators believe he may have been exposed to ammonia.
Martinez worked for Blick's Phosphate which is a subcontractor for Simplot.
The Garden City, Kansas, native was taken by ambulance to Portneuf Medical Center where he was later flown by helicopter to Salt Lake City. Martineze was pronounced dead at that hospital on Wednesday.
Kenny Kalb, spokesperson for Blick's, said the cause of the incident is still under investigation.