After a three-month investigation into the April 13 machine shop accident that killed Michele Dufault ’11, the Occupational Safety and Health Administration found that Yale failed to provide necessary safeguards and education to prevent injury to students.

OSHA investigators did not find specific hazards to worker safety — Dufault was a student and not employed by the University — so the agency could not levy fines against Yale. Investigators still issued seven recommendations for improving machine shop safety at Yale in a letter sent to University General Counsel Dorothy Robinson on Aug. 15. But Yale is denying that it is at fault for the deadly accident and alleges that the report itself is flawed.

“Yale has reviewed OSHA’s letter regarding its investigation of the accident, a letter which apparently was shared first by the agency with the media. Unfortunately, OSHA’s assessment contains a number of significant inaccuracies,” University spokesman Tom Conroy said in an email to the News last week.

The OSHA letter described the lathe’s rotating lead screw as central to the accident. According to the letter, federal law requires a shop operator to provide external safeguards for a lead screw that is completely exposed without protection.

OSHA investigators found no physical guarding, personal protective equipment or even emergency stops on the machine that killed Dufault. But a Yale Police Department report about the incident offers a somewhat different picture of the lab and indicates that some safety guards might have been in place in the lab after all: The report says that, when Dufault’s body was discovered by two male undergraduates, they “immediately turned off the machine by pressing the emergency stop button.”

OSHA officials declined to elaborate on any of their findings from the investigation, including the disputed presence of an emergency stop.

Conroy said the lab’s lathe met all American National Standards Institute regulations, which incorporate both training and personal protective equipment.

OSHA listed several other areas of concern: Site safety inspections and audits of the shop conducted by the University did not address machine safeguarding, and the shop did not post any general rules and regulations — including caution signs — for using the lathe or any of the other equipment in the room.

The agency alleged that student training is currently lacking. Kowalski wrote in his letter that Yale should “develop and implement a formal training program (including a course outline, curriculum and training records) that meets the requirements of all ANSI standards.” But Conroy said the University’s current training system meets industry standards.

“Machine tool training provided by Yale was extensive, consistently reinforced by professional staff, and confirmed by Yale’s expert to be exemplary,” he said, adding that “students were repeatedly instructed not to use machinery without a buddy present.”

The Yale Police report said that students are only allowed to access the machine shop if they have completed a semester of “Laboratory in Instrument Design and the Mechanical Arts,” a graduate-level chemistry course. David Johnson, a research support specialist who co-teaches the course and oversees the machine shop, is cited in the police report as saying that “safety is discussed and, in fact, emphasized during and throughout the semester.”

The police report indicated that only five other students — including both undergraduates and graduate students — were allowed 24-hour access to the shop.

During its investigation, OSHA identified the machine as a Harrison-Claussing lathe manufactured in 1962. According to the letter, the University could not determine when the machine had been purchased. In interviews with OSHA staff, faculty could only confirm that the equipment had been at the facility since at least 2000.

After Dufault’s accident, OSHA spokesman Ted Fitzgerald said the agency was not immediately sure if the machine shop in Sterling Chemistry Lab fell under its jurisdiction, because Dufault was a student. But because University employees also use the machine shop, he said, the agency began an investigation. OSHA’s stated mission is to enforce safety standards for employees in the workplace.

“If there was a possibility there was hazard that might affect employees, then we would want to look into it,” Fitzgerald said in April.

Following the incident, Yale administrators pledged to investigate the accident on their own to help establish new procedural guidelines. Conroy told the News in July that the committee Yale established to examine shop safety has “done a great deal of work on all aspects of the shops,” including access and monitoring guidelines, safety equipment and training regulations.

Conroy estimated in July that the internal committee’s final recommendations would be published and officially implemented around the beginning of the school year.

Conroy told the News last week that, although they had not yet been released, some of these recommendations were already going into practice, including “increased awareness by users of safety rules,” and the presence of monitors in shops at all times when undergraduates are working.

“When something like this happens we want to be entirely confident that we have the right policies and procedures in place to protect our students,” University President Richard Levin said in an interview with the News on the day Dufault died.

The official cause of Dufault’s death was “asphyxia due to neck compression,” according to Connecticut Office of the Chief Medical Examiner investigator Kathy Wilson.