Voters in the Mesa Union School District will decide next month whether to tax themselves to pay for campus safety improvements.

The single-school Somis district of about 575 students has placed a $4 million general obligation bond measure, called Measure A, on the June 3 ballot.

If it is approved, plans call for relocating a Mesa School playground that borders a busy section of Highway 118 and underground high-pressure gas lines, as well as making improvements to the campus parking lot and entrance, where traffic regularly backs up onto the highway.

Property owners would pay about $29 annually per $100,000 of assessed property value, for no more than 25 years. The measure requires a 55 percent majority to pass.

"We're focusing on safety," said school board President Susan Nemets, who has two children at Mesa. "It's not a hard sell for anybody who has been to our school."

Expanding the parking lot and moving the entrance to allow a longer turning lane on Highway 118 should ease congestion, school officials say. They plan to purchase adjoining land to make those changes and to develop a new play field.

The former play field has been closed to students since underground gas lines were discovered along the fence line, said Superintendent John Puglisi. Students participated in physical education classes, played at recess and held after-school games on the field, but now they are limited to a small grassy area.

California safety guidelines required the district to stop using the field and identify measures to reduce risks to students.

School officials looked at moving the campus to another location, but plans developed in the 1980s turned out to be more cost-effective while still reducing the risk.

The plans call for expanding the campus onto the adjoining land, which would make room for a new play field. Puglisi said a wall might also have to be built.

As a safety issue, the work has to be done, Nemets said, and the bond measure would make it possible for the district to come up with its share of the cost.

The district has already paid about $500,000 on various studies required by state agencies. If Measure A passes, the district hopes the state will pick up 60 percent of the cost, officials said.

A citizens oversight committee would be formed to make sure the bond money is spent on the approved projects, which do not include administrator salaries.

The last bond measure in the district was approved by voters in 2001 for $3.9 million. That money was used to modernize the 1930s-era campus, including electrical, sewage and plumbing upgrades.

No official committee has been created to promote Measure A, but, Nemets said, information has gone out to parents and proponents in the next few week will be urging people to head to the polls to support it.

"The school at Mesa is such a unique place," she said. "Everyone there looks out for each other." The bond measure, she said, is another chance for everyone to pitch in and keep the school safe.