WEST HAVEN — The last reported “crime” at Yale’s 136-acre West Campus occurred four to five years ago, said Thomas Paddock, one of the four head security officers who cover the area. An employee’s lunch was stolen.

“The employee was really mad,” Paddock said. “So we had a sign placed saying, ‘Honor thy neighbors’ lunch.’ ”

In fact, no crime warranting police enforcement occurred in the 20 years that Bayer HealthCare Pharmaceuticals occupied West Campus, a Bayer spokeswoman, Rosemarie Yancosek, said. And Vice President for West Campus Development Michael Donoghue said in an interview this week that no crimes have occurred on West Campus since Yale purchased the lot in 2007. With only about 90 employees, an experienced security team left over from Bayer and tight security procedures — including limited access for visitors without appointments — West Campus is a safe, crime-free environment, Yale officials said.

“There is not the level of occupancy or comings and goings as we experience on the New Haven campus,” University Deputy Secretary Martha Highsmith, who oversees Yale security, said last week.

So for West Campus security officials, including Director of West Campus Security Francisco Ortiz, life has not been difficult. The main job for the West Campus security force is to patrol the grounds to keep an eye out for potential hazards, such as broken lights, and to notify facilities workers to fix them, West Campus security officials said. Paddock — as well as Highsmith, Yancosek and other officials — said police have never conducted a criminal investigation at the site. It is much easier to protect an area when you can control who enters, he said.

There are four entrances to West Campus, but the only one accessible to the public is the Visitor’s Center, which is staffed by security officers in shifts 24 hours a day, seven days a week. There is also a gate on Heffernan Drive that is used by delivery trucks and construction vehicles and is staffed by an officer from 6 a.m. to 6 p.m., Paddock said. The other two, the Morgan Lane and the Bayer Research Center gates, are employee-only and are manned by security cameras that feed information to the visitor’s center, Paddock added.

Only West Campus employees are permitted to wander through the buildings, said Judy Steinis, who spent 25 years with Bayer and has spent the last two years as West Campus’ security supervisor. When visitors arrive, they must have an appointment, which must be confirmed by the person they are visiting, Ortiz said.

Though they are not permitted to enter the buildings, Steinis said, people with Yale IDs can walk on the grounds, which contain nature trails and a section of the Oyster River.

“You can see deer, turkey roosting on branches and building ledges, jackrabbits and the occasional fox,” Steinis said. “We even have a birdwatching group with the Peabody where they’ll go out at lunch and see what birds they can identify on campus.”

Paddock said there have been no examples of physical threats — unless you count the wild turkeys. One of Bayer’s corporate vice presidents was afraid of large birds, Paddock said, and would call security to get the turkeys away from her car.

Ortiz said workers at the gated research facility do not face the violent security situations, such as muggings and shootings, common in an open, urban center like New Haven. His life has gotten easier, he said; he previously dealt with life or death situations — such as murders — on the streets of New Haven. After all, before he took his job as head of West Campus security, he served as chief of the New Haven Police Department. Ortiz vacated his position as NHPD chief in January 2008, six months after a scandal in the narcotics department resulted in the firing of three NHPD officers, two of whom were sentenced to federal prison time.

In an interview Thursday, Ortiz hesitated to compare the two roles.

“What a police chief is responsible for and what a director of security is responsible for is very different,” Ortiz said. “New Haven is a city of over 125,000 residents and West Campus is a very small population, and we’ve only been here for just under two years.”

But West Campus may face more crime in the near future.

“Even though we’re not well populated,” Ortiz said, “we will be.”

Highsmith and other Yale officials said she has been focused on planning for the University’s increased use of West Campus, which houses science and arts facilities. She has met with security officers at West Campus, as well as officials from Orange and West Haven, to discuss security. The security force has been meeting with West Campus workers, who include employees affiliated with the Peabody Museum and the Yale University Art Gallery, landscapers, maintenance workers and former Bayer researchers.

For now, the security officers at West Campus can say there has been only one incident: the missing lunch. The security team treats each report very seriously, Paddock said. There were about 20 people using the refrigerator where the lunch was last seen, Paddock said, so food can sometimes get misplaced.

“Crime just doesn’t happen here,” he said.

Lindsay Gellman and Colin Ross contributed reporting.