FREDERICK COUNTY, Va. The dispatch traffic starts like an ordinary night. A status check. A dark red Altima parked against the trees behind a business on Double Church Road with a phone on the seat. A smoke detector on South Loudoun Street that will not stop chirping. Then, at about 20:09, the tone changes.

“Vehicle crash, 81 in the area of the 310, a vehicle hit a semi, vehicles are exploding.”

What followed over the next hour on Frederick County Fire and Rescue’s channel 3 is the account of Thursday night’s crash that no press release has caught up to yet. This desk obtained the audio. The units are identified by number and the traffic is reproduced as spoken.

The first arriving unit reported a tractor-trailer rolled over in the median and on fire, with a passenger car involved. Dispatch sent Engine 18, Medic 18, and Rescue Squad 21, then Winchester Squad 2, Company 11, and Battalion 10, and asked a unit coming up northbound to “just shut down the interstate, please.” A caller relayed that the truck “blew up again after the driver got out” and that the driver might be lying on the ground near the tractor-trailer. Unit 314 reported, “Projectiles coming up off the tractor-trailers.”

Then the cargo. “Trucker advised that he was hauling oxygen tanks.” A minute later, to every unit responding: “Tanks are still exploding, throwing debris into the roadway. Caution.”

Compressed oxygen does not burn, but a cylinder in a fire vents through its relief valve or fails, and the oxygen it releases turns every combustible on the scene into a torch. The explosion witnesses recorded on video, and the fireballs that lit up the interstate, were cylinders letting go one after another. Command later confirmed: “It appears that all cylinders have already released. I’ve got no active relief valves in progress. No more explosions.” Until that call, firefighters were working inside the debris radius.

They were working around a patient. Unit 314 was doing CPR. Rescue Engine 11 reported the patient in cardiac arrest “in front of the police vehicles in the southbound lane,” and a deputy on the radio said they were “trying to move the patient; they’re dodging debris.” About 20 minutes into the incident, Rescue Engine 11 took the patient to the hospital, priority one, CPR still in progress, and abandoned Engine 18’s unit on the roadway to do it. The radio does not identify the patient. The sedan’s driver, a single occupant, was located in the median, uninjured.

The deputies who reached the patient first did so while their own cars burned. “Confirmation on your deputies,” a unit told command, “it appears that their cruisers are on fire at this time.” Command’s reply: “I’m not worried about the cruiser; I want accountability for the deputies.” Roughly an hour in, dispatch confirmed all law enforcement officers accounted for. Engine 12 was assigned to knock down the fire on the cruisers.

Then the truck’s configuration came clear. “It appears we’ve got a piggyback tractor-trailer, possibly two tractor-trailers.” A second tractor-trailer, on the shoulder of the northbound lanes, was “pretty well involved,” and a rear piggyback trailer was burning too. Fire blocked the northbound lanes. Whatever the state police determine about the sequence, the radio describes two heavy units burning on opposite sides of the interstate.

The rest of the hour is about water. Engine 18 reported out. Rescue Engine 11 was at a quarter tank. Engine 12 went dry. Command called for a tanker from the south side of the county, another from the north, and mutual aid from Clarke County, then had to route them: the ramps at Route 37 were packed with stopped traffic and a tanker could not get down them, so units were sent in off Fairfax Pike, off Route 11 from Stephens City, and down the northbound lanes from mile 313 through a crossover. Command’s decision, on the radio: “Let’s just keep the fire in check. Don’t worry about full extinguishment. And protect any additional exposures.” The fix came from Ops 10, who had driven the southbound side and spotted the hydrant on Tasker Road next to Frederick Water. Winchester Engine 4 and Wagon 4 were sent to it, and crews stretched a supply line across the road, with deputies holding traffic.

VDOT’s TRIPS safety patrol arrived with a sign truck and took over traffic control. Emergency management was on the phone with VDOT. Both directions of I-81 stayed closed.

Two things the radio does not settle. It does not say what caused the initial collision or which vehicle left its lane; the first call describes a vehicle hitting a semi, and the sequence belongs to the Virginia State Police. And it does not name the patient in cardiac arrest, or the truck driver, or say whether they are the same person.

What it does settle is the shape of the night: a truck full of oxygen cylinders burning in the median at a spot where a South Carolina driver died in a crossover 79 days earlier, deputies pulling a patient in cardiac arrest out from between their own burning cars, and a fire ground on the busiest truck corridor in Virginia that had to send for water from two counties.