Every day at San Francisco General Hospital you will see something that cannot be unseen. The unthinkable is quotidian here; San Francisco General is Dante's Inferno meets Fellini Satyricon, only with bloody scrubs instead of robes.

And yet, in the past few months, two events transcended the hospital's daily madness and shocked the general public. On Valentine's Day, a 93-year-old named Mary Perez was attacked and beaten by a mentally unstable fellow patient. On Sept. 21 of last year, Lynne Spalding shambled out of her room in the telemetry unit. Following a grotesque litany of procedural missteps, her corpse was discovered in a stairwell on Oct. 8.

The hospital's nurses are now in the midst of contract negotiations. But, in a trove of documents obtained by SF Weekly ­— long predating the ongoing negotiations or either incident ­— they claim inadequate staffing levels and portend calamities to come.

"We believe the current staffing level is dangerous and is directly compromising the delivery of safe patient care," the emergency department nursing staff wrote en masse to management in an October group letter ­— months prior to the Perez incident.

On the very day of that attack, four nurses filed an "Assignment Despite Objection" form claiming "less staff has been provided than is normal or safe for patient care" and warning of "unsafe conditions on multiple violent patients and no sitter available."

The job of a "sitter" is just what you'd think: to keep an eye on problem patients. Hours after the nurses' complaint, a 29-year-old man named Orin Zebest on a psychiatric hold ­— a condition hospital policy dictates should require a "sitter assigned to patient at ALL times" ­— leaped from his gurney, ran into Perez's room, and beat the nonagenarian with her IV pole.

The bizarre concatenation of events that led to Spalding eluding hospital authorities, dying, and remaining undiscovered for weeks required a Chernobyl-like chain of errors and poor judgment. But, had a sitter been stationed to her, she never would have gotten out the door. There wasn't one; nurses say that particular staffer was pulled to other duties and forced to "prioritize on the fly."

Nurses in the unit housing Spalding have complained to SF Weekly about reduced staffing before her disappearance and continuing to this day. A complaint from shortly before she went missing laments "reduction in support staff."

In fact, the hospital is currently staffing 15 percent fewer nurses than it's budgeted to carry ­— a move nurses characterize as a cost-cutting measure.

Hospital spokeswoman Rachael Kagan flatly stated that staffing is "adequate." As for Spalding and Perez, Kagan claimed that multiple investigations failed to tie either incident to "any shortage in staffing."

Nurses beg to differ. And, unlike that doomed patient, this is a point of contention that's unlikely to disappear.