Date: 202101
Local time of day: 1801-2400
Location: ZZZ.ARTCC, US
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Second aircraft: Small Aircraft; High Wing; 1 Eng; Retractable Gear
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Confusion; Distraction; Time Pressure; Situational Awareness; Human-Machine Interface; Workload; Troubleshooting; Training / Qualification
Anomaly: ATC Issue All Types; Airspace Violation All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Provided Assistance
Contributing factors: Procedure; Human Factors; Airspace Structure; ATC Equipment / Nav Facility / Buildings; Environment - Non Weather Related
Primary problem: Environment - Non Weather Related

Narrative: I am an Air Traffic Controller. It is my job to keep people safe while maintaining an orderly and efficient flow of Traffic. All of that was thrown out the window this night.  I was instructed by management who were following orders received from the Command Center to ship numerous aircraft into a black hole (ZZZ1 ATC Zero). These pilots and passengers left the safety of a radar environment with no radio communication; no approved separation; and no one watching over them.The first ZZZ1 went ATC zero for COVID cleaning in the middle of the day and it completely overwhelmed the ZZZ2 [Center] controllers.  The sectors became completely unmanageable.  Aircraft from ZZZ1 Center entering ZZZ2 [Center] checked in responding to an RA.Training was insufficient and we were not prepared for what was about to happen.  The last time I received training on non-radar separation was in 20XX in a classroom in Oklahoma City. I had no real-life experience with it until this week.I arrived at work I received a verbal briefing from my Supervisor.  I was handed a sheet covered with tons of airports; routes; altitudes requirement; and minimal phraseology.  Not only was this an insufficient amount of time to absorb the information; the instructions on the sheet were incorrect.  We were told to get estimates over a fix and make sure he had 10 minutes between aircraft.  In actuality we were supposed to assign a time for them to cross the fix.  Also; the phraseology we were given when switching the aircraft did not include 'radar service terminated.'  It was only after I got off position I realized that I had not given that critical piece of information to the pilots.I was so busy trying to sort out who needed what route and what was the appropriate altitude that I was unable to print strips and pass estimates.  Knowing I was overwhelmed I called for help on 2 occasions.  However; management and the tracker were so busy helping other people that they could not hear my calls for help.  The information sheets we were given had so much information on them it was very difficult to know who needed what.  At one point my information sheet was being used by another Controller.  This made it very difficult to know what I needed to do with the aircraft.  It was a very chaotic situation for everyone.As soon as I was relieved from my position I immediately notified my Supervisor that I had not passed any strips or estimates.  I left with a sinking feeling in my stomach not knowing if the planes I shipped were actually separated.  Concern over whether they made it through the black hole and arrived safely to ZZZ3 [Center] weighed heavily on my mind.Below are a few examples of Aircraft that were placed in dangerous situations as a direct result of the decision to misapply non radar rules and by allowing ZZZ1 [Center] to go ATC zero in the middle of the day during peak traffic times.Aircraft X- Took the clearance and left ZZZ2 [Center] airspace entering ZZZ1 [Center] ATC zero airspace.  At some point the pilots realized that they were not allowed to fly non radar.  Since they were no longer in communication; they turned their plane around and flew back into ZZZ1 [Center] airspace without a clearance.  This jeopardized the flight because they were at FLXXX.  This was an altitude we were using to clear aircraft through ZZZ1 [Center] airspace on non-radar routes.  No separation was provided for this flight and they may or may not have had a loss. I have no idea if he was head on with another aircraft at the same altitude.  This was an extremely dangerous situation.Aircraft Z - Level at XX;000 feet in ZZZ1 [Center] airspace.  ZZZ1 [Center] updated his data block to VFR and put him on my frequency.  ZZZ1 [Center] did not call and coordinate anything on his flight.  The pilot checked in stating he was on an IFR flight plan in IFR conditions and wanted to climb to get out of the clouds.  I told him I did not have authorization to change his altitude and if he could climb VFR to get out of clouds it would be OK.  In hindsight this actually may have been an emergency.  If he was in fact VFR like his data block indicated; he may have been VFR in the clouds.  He later reported that he was VFR on top at XY;000 feet.  Additionally; ZZZ1 [Center] put this aircraft on my frequency and he never even entered my airspace.  At XX;000 he would have entered ZZZ [TRACON Airspace].  At XY;000 he entered the sector adjacent to me.Aircraft Y - Checked in about 15 miles inside ZZZ [TRACON] airspace level at X;000.  The pilot said he was on an IFR flight plan; in the clouds and ZZZ1 told him to contact me.  This Aircraft also never entered my airspace.  I am almost positive that ZZZ1 [Center] violated ZZZ [TRACON's] airspace with this aircraft.Another aircraft had some confusion on his clearance limit.  While in ZZZ1 ATC Zero [Center] airspace he entered into holding and was calling for help.  After holding for an unknown period of time he became low on fuel.  Eventually he was able to get a hold of someone and land at a nearby airport.  This incident is deeply concerning.  This aircraft was holding and eventually descended to land while we launched numerous aircraft through this area.  How many losses of separation might we have had with just this one plane?  He was also in distress and had difficulty reaching an Air Traffic Controller for help.  This is a prime example of why it is important to maintain communication with aircraft while they are in a non-radar environment.We had two Aircraft at FLXXX with less than 2 miles separation when they reached ZZZ4 Center's airspace.  Apparently; there was a major speed overtake and the trailing aircraft caught up to the lead aircraft.I had an aircraft checked in from ZZZ4 Center who informed me that their estimate over the fix was way off.What we did this day was in violation of the 7110.65 non radar rules and Federal Aviation Regulation for pilots.  During non-radar; pilots are required to stay in communication with air traffic controllers and report time checks to make sure separation is maintained.  These pilots had no radio communication and were never assigned a time to cross the fix.  Also; controllers working the aircraft had no way to keep track of who had what time.  We were asked to pass the time to the Supervisor; an impossibly task given the circumstances.  We also flooded the route with significantly more aircraft than were intended to be on them.  The volume was too high and unmanageable.Everyone working that day knew this was a bad idea.  Union; Controllers; supervisors; upper management and our facility chief all knew this was unsafe.  We expressed our concerns but were ignored and forced to proceed.  I cannot express how deeply concerning and unconscionable this scenario was.  We are lucky that we did not have a mid-air or an aircraft in distress that resulted in an accident because they could not receive assistance from ATC.  These pilots and passengers were on their own.  On this day we were most definitely NOT the safest airspace in the NAS.  Without the proper tools and training in place this is an extremely unsafe situation.  Interference with Air Traffic Control facility services can lead to loss of life.We need proper training and practice before we are ever asked to do this again.Rules and regulations must be adhered to.Radio communication should be kept between ATC and pilots at all times.We should not overwhelm the controllers.  Traffic reduction is a must in situations like these.A tracking sheet should be kept at the scopes to know who was assigned what routes and times over the fix.Extra staffing should be called in to work these extreme situations.After major events there should be study groups put together to come up with better procedures.  Air Traffic Controllers and supervisors that worked the traffic should be included in these study groups.When controllers; management and union say this isn't safe or we shouldn't do this then extra precautions should be taken.  We are here to work traffic. We know better than anyone what [the] limitations are.  Our voices should be heard and when we say something isn't a good idea we are probably right.




Synopsis: Center Controller reported safety concerns with another Center facility going to ATC Zero during peak traffic times and the confusion/stress this causes the controllers.