Narrative:

A firefighting tfr recently went into effect south of ZZZ airport. Aircraft X (small aircraft) was overflying that area in a route that kept them clear of the tfr. Firefighter aircraft Y was in the tfr and briefly flashing conflict alert with aircraft X. Aircraft Y was in the tfr and I believe it was level at X;XXX feet when I saw it. At this point I suppressed conflict alert believing that it was conducting normal firefighting operations and maneuvering within the tfr. Aircraft X was approximately 7 miles outside of the tfr. Shortly after suppressing conflict alert; I lost sight of aircraft Y; believing it was operating in a cluster of firefighting aircraft in the tfr; I went to perform other tasks. Less than a minute later; conflict alert went off again; I looked down and aircraft Y and aircraft X were separated by 100 feet and less than a mile. Both aircraft were VFR and aircraft X was receiving flight following. Aircraft Y; a high performance jet aircraft exited the tfr; rapidly climbed and almost ran into aircraft X that was in close proximity to the tfr. I'm unsure of weather aircraft Y was lost on the radar at the time; its tracking on system but none of the other firefighting aircraft are. In either case; I didn't see it again until it was in close proximity to aircraft X. I called a traffic alert; aircraft X acknowledged saying he had them in sight.turbojet aircraft should be legally required to have flight following at all times.

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Original NASA ASRS Text

Title: Center Controller reported a conflict between a firefighter aircraft in a fire TFR area and a small aircraft near the TFR.

Narrative: A firefighting TFR recently went into effect south of ZZZ airport. Aircraft X (small aircraft) was overflying that area in a route that kept them clear of the TFR. Firefighter Aircraft Y was in the TFR and briefly flashing conflict alert with Aircraft X. Aircraft Y was in the TFR and I believe it was level at X;XXX feet when I saw it. At this point I suppressed conflict alert believing that it was conducting normal firefighting operations and maneuvering within the TFR. Aircraft X was approximately 7 miles outside of the TFR. Shortly after suppressing conflict alert; I lost sight of Aircraft Y; believing it was operating in a cluster of firefighting aircraft in the TFR; I went to perform other tasks. Less than a minute later; conflict alert went off again; I looked down and Aircraft Y and Aircraft X were separated by 100 feet and less than a mile. Both aircraft were VFR and Aircraft X was receiving flight following. Aircraft Y; a high performance jet aircraft exited the TFR; rapidly climbed and almost ran into Aircraft X that was in close proximity to the TFR. I'm unsure of weather Aircraft Y was lost on the radar at the time; its tracking on system but none of the other firefighting aircraft are. In either case; I didn't see it again until it was in close proximity to Aircraft X. I called a traffic alert; Aircraft X acknowledged saying he had them in sight.Turbojet aircraft should be legally required to have flight following at all times.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.