Robert Patrick's character comments that "Ray Pierce has become some kind of metal man. Because that only happens in the movies, Agent Scully." Scully smirks with a response, "Does it, Agent Doggett?" Patrick played the liquid-metal Terminator in Terminator 2: Judgment Day (1991).
Loosely based on Tetsuo: The Iron Man (1989), a 1989 Japanese cyberpunk film by cult-film director Shin'ya Tsukamoto. X-Files staff writer Jeffrey Bell wrote this episode before Robert Patrick was cast in the show.
The three scientists featured in the episode - Chamber, Clifton and Pugovel - were all named after friends of writer Jeffrey Bell.
Jeffrey Bell's final The X-Files (1993) episode. He would join the writing team for Angel (1999) the following year.
At the time of this episode's writing Gulf War Syndrome had not yet become widely accepted in the military or medical field, partly due to the widely different kind of symptoms experienced, including: fatigue, muscle pain, cognitive problems, insomnia, rashes and diarrhea. Recognition of the syndrome would later change due to the sheer number of veterans of the war (on both sides) showing unusual symptoms. A report released in April of 2010 by the US Department of Veteran Affairs of a study done by the US National Academy of Science showed that some 250,000 of the 696,842 U.S. servicemen and women in the 1991 Gulf War continue to suffer from chronic multi-symptom illness, which became officially known as Gulf War Illness, the study also found it continued to affect many of them more than 20 years later. Another study published by the Royal British Legion found that as many as 33,000 UK Gulf War veterans could be living with the syndrome, with 1,300 claiming a medical pension related to their service in the Gulf War. A specific singular cause of the illness has yet to be identified but doctors and scientists from the US, UK and Iraq generally agree that it is likely a combination of the following: exposure to pesticides, repeated use of pyridostigmine bromide (a medication used to help protect soldiers from nerve agents like sarin), exposure to the different chemical weapons and nerve agents used by the Iraqi military (anthrax, sarin, ricin, mustard gas), side effects to the then experimental anthrax vaccine and radiation exposure from depleted uranium shells.