The next morning, when investigators entered the incinerator charging room, they noted intense heat emanating off the sliding hatch doors and the smell of charred, rotten meat. Cook and his maintenance crew were nowhere to be found. All had called in sick that day, something that had never occurred before. Safety officer Dr. Jerry Walker — once described by a reporter as "thin, of average height, sort of Southern-square looking… reserved to the extreme…in all, decidedly odd" — was chair of the investigation committee. He led an examination of the crime scene. The air intake had been blocked, and the supply intake ducts to the incinerator were jammed wide open. Outside light shined into and air flowed out of the room, a chamber that was supposed to be sealed to the outside world. A committee member pointed out lead tape applied across the latch of the emergency door, which now hung slightly ajar. Dr. Walker ordered the openings blocked at once. The filter housings had been sprayed with lye by Cook's crew, so they couldn't be tested. But then they spotted an unthinkable sight. "Several filter units had media improperly installed with gaps up to three-quarters of an inch," the committee reported. That meant that at any one given time, no less than 750,000 viruses could be exiting the building, marching out side by side. When Wiggin turned on the air pressure system, the supply fan started before the exhaust fan. For the air pressure to contain germs properly within the room, it had to start in reverse order. Stunningly, the electricians had wired the safety interlock backward.
Dr. Walker paged through the incinerator log and spoke with the employee who kept it. He shook his head as he read the same static pressure number recorded for each and every kill day. Either the gauge did not function, or the worker dummied the logs. Standing over the shoulder of the log keeper, listening to him try to explain the log entries, Walker realized the numbers "had little meaning to him." Concealing disgust, he flatly reported, "It is apparent that a knowledge of pressures is essential by someone during incineration with responsibility to maintain control of the pressure required."
During the following week, Merlon Wiggin and his assistant climbed up onto the Lab 101 roof and inspected the 107 air-filter units. On the roof stood a mechanical garden of metal stacks that sprouted out of the black tar roof — some short and some long, some wider and taller than the men — all anchored with wire stays. As a nippy October wind swept off the Sound and crept up their backs, they heard the collective whirr of the air filter fans.
If the incinerator was in bad shape, the condition of the roof was even worse. The rubber gaskets designed to seal the gaps between the air filters and roof masonry were brittle, cracked, and leaky. Some gaskets were altogether missing. The filter housings were installed in such a way as to leave openings "allowing the complete passage of air without the benefit of filtration." It was as if someone with no training ripped an old one out and slapped a new one in, giving the task zero thought. The ductwork had holes punched into it. Replacement filters were much thinner in size than those used in years past. Wiggin's roof tour was disturbing, and its ramifications were nothing short of terrifying.
The inside review was just as scandalous. The air pressure logbook for experiment rooms during four weeks prior to the outbreak wasn't even dummied like the incinerator logbook — the pages were blank. Wiggin found many lab rooms way out of proper air balance and some were positive to the outside, meaning that germs were being circulated through the entire laboratory building. Bad air, "hot" with viruses, was being forced to exit somewhere. It had a choice of possibilities — through heavy paper and charcoal filters designed to catch germs or through the easier path, via gaping holes in the roof. To top it all off, he found no air filter maintenance. The rubber gaskets hadn't been changed in nearly thirty years (when they were first installed in the early 1950s), rendering each air filter between the defective gaskets virtually useless. And they weren't the only filters in question; some of the sewage vent filters, which strained biologicals out of animal wastes, were in poor condition, and a few were even missing. The appalling condition of the laboratory shocked Wiggin.
It became painfully clear why Wiggin's foreman, Truman Cook, and his crew were feverishly tinkering with repairs the day before, and why they called in sick today, the day the committee began its investigation.
Try as he may, there was no way the chief engineer could bring himself to certify the blatantly porous building as safe. "Recommend that Lab 101 not be considered as a safe facility in which to do work on exotic disease agents," Merlon Wiggin told the investigation committee, "until corrective action is accomplished." That included smoke-testing each filter after the repairs to see if any air continued to escape.
Digesting Wiggin's disquieting findings, Director Callis and safety officer Dr. Walker grew increasingly uncomfortable. Research experiments were backing up and a special project with the Rift Valley fever virus project was far too important to be delayed. Unwilling to accept the dire assessment, they ordered Wiggin to begin smoke tests and continued virus production and animal experiments under a pack of faulty air filters. "No new activities are expected to be taken on over the next several weeks…"wrote Dr. Callis in a letter to Washington, "… beyond those commitments already made." In other words, on with the work. Setting off smoke bombs in the incinerator and lab rooms, Dr. Walker and Mr. Wiggin watched harmless white wisps of smoke waft through cracks, gaps, and holes, visible stand-ins for deadly germs hundreds of times smaller that were escaping. Not one of the laboratory's 107 air filters was salvageable. All of them had to be scrapped and new mountings installed.
But well before the air filters were fixed, Plum Island scientists continued their infectious virus research, in a porous lab facility they knew was inadequate to contain the germs safely.
The committee rendered its final report to Dr. Callis on January 9. Of Plum Island's three lines of defense — the containment laboratories, restrictions on personnel and material, and the island location — the first two had failed. Their best guess as to what happened went like this: one of the animal handlers walked into the Building 62 holding pens to feed the animals as he routinely did. While they ate, the handler cooed at the beasts and petted them lovingly, as they were prone to do, and unwittingly fed them helpings of viruses along with their meals.
But that didn't explain how one of the animal handlers, restricted by the rules from entering the laboratory building, became a carrier of the virus. Investigators turned their attention to the incinerator room and the 107 air filters on the lab roof. Dr. Walker's impressions of the incinerator logbook were true. For years, no one set the internal air pressure equal to the atmosphere, as required by the rules during a burn. Because of this negligence, "the entire area had been pressurized to the outside atmosphere," which meant the exhaust was literally blowing contamination out of every crack and crevice into the sky.
The other theories, not fully reviewed by the investigators, involved the construction work. During heavy rains, water seeped under a plywood barrier into the incinerator room and then retreated back out. "They were digging the hole for the flue and chimney stack and we had torrential rain for a week," remembers one worker. Dirt near the plywood was excavated and hauled to a site three hundred yards from the Building 62 pens. The committee omitted another occurrence that may have played a role. "Supposedly it was caused by a leakage of sewage," says Ben Robbins, a retired Plum Island engineer. A local subcontractor ruptured an underground pipe that carried contaminated wastewater from Lab 101 to Building 102, the decontamination plant. Perhaps infected sewage seeped into the dirt that was later moved next to Building 62.