Narrative:

Was at the fuel pit fueling up the line truck; received a call to go to gate a to service oxygen on a crj-200 aircraft. Arrived at the scene and opened up the rear tail gate [of the line truck]. I saw one bottle secured to the bed. It was green in color; with no visible warning sign that I can recall. I noticed a steel braided line attached to the regulator that was wrapped to the tail gate. I did not see the service end. I looked around and found the service kit in the flip top. Enclosed was a regulator and braided line attached. Instead of removing the existing regulator; I swapped line and serviced the aircraft with 120 psi of gas. First day back to work; late afternoon; after getting back to the gate; I installed what I thought was a missing bottle of nitrogen [in the line truck]. After further inspection I found that the bottle that was already installed in the truck was nitrogen and not oxygen. I immediately notified my manager of the issue. I believe when I looked in the tail gate I saw a green bottle and didn't see any obvious abnormalities. I assumed the steel braided line was the same type we used in the hangar on the oxygen servicing bottle. The bottle didn't have a different regulator like we had on the high pressure bottle; but yet the same color and similar design. Noticed four days later as the oxygen bottles used for hangar servicing. [Recommend] better placard and warning signs around all gas bottles. [And] more distinctive regulators use for each type (color). Servicing at gate.

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Original NASA ASRS Text

Title: Four days after servicing crew oxygen on a CRJ-200 aircraft; a Line Aircraft Maintenance Technician (AMT) realizes the green bottle he used was actually a nitrogen bottle. Aircraft was grounded shortly after.

Narrative: Was at the fuel pit fueling up the line truck; received a call to go to Gate A to service oxygen on a CRJ-200 aircraft. Arrived at the scene and opened up the rear tail gate [of the line truck]. I saw one bottle secured to the bed. It was green in color; with no visible warning sign that I can recall. I noticed a steel braided line attached to the regulator that was wrapped to the tail gate. I did not see the service end. I looked around and found the service kit in the flip top. Enclosed was a regulator and braided line attached. Instead of removing the existing regulator; I swapped line and serviced the aircraft with 120 psi of gas. First day back to work; late afternoon; after getting back to the gate; I installed what I thought was a missing bottle of nitrogen [in the Line truck]. After further inspection I found that the bottle that was already installed in the truck was nitrogen and not oxygen. I immediately notified my Manager of the issue. I believe when I looked in the tail gate I saw a Green bottle and didn't see any obvious abnormalities. I assumed the steel braided line was the same type we used in the hangar on the oxygen servicing bottle. The Bottle didn't have a different regulator like we had on the high pressure bottle; but yet the same color and similar design. Noticed four days later as the oxygen bottles used for hangar servicing. [Recommend] Better placard and warning signs around all gas bottles. [And] More distinctive regulators use for each type (color). Servicing at gate.

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.