While most students spent the summer free of homework, some teachers were hard at work on an assignment.

A group of elementary school teachers in the Mt. Lebanon School District received a state grant to brainstorm ways to infuse environmentalism into the existing science curriculum, and they gathered around a conference table earlier this month to share the fruits of their labor.

A standard second-grade unit on "changes," for example, could include a lesson on recycling, which could carry over into other subject areas, said Jefferson Elementary School teacher Debi Mercier. "The idea of the environment isn't something that's only in science. It has a direct connection with social studies."

As more public attention is focused on environmental issues, school districts this year are going to never-before-seen shades of "green."

Where environmental correctness used to involve a basic recycling program or an outdoor education class, districts now are coming up with programs, practices, curriculums -- and even new buildings -- that emphasize environmental awareness.

In the Pine-Richland School District, the new Eden Hall Upper School has all sorts of energy-saving features.

Infrared sensors in classrooms detect whether people are in the room -- and turn off the lights when a room is vacant. Natural lighting, including skylights and large windows, reduces the need for electric lights.

"We're teaching kids about science, and in a lot of our discussion today in current affairs and current trends, we're trying to be more energy efficient," said district spokeswoman Rachel Hathhorn. "It's just kind of a way of life now and to promote that with our kids is important."

The new school building also has a white roof to reflect sunlight, wood paneling on some walls to keep more heat in the building and grass that doesn't need to be mowed to reduce pollution from lawnmowers.

In its renovation of Deer Lakes High School, the Deer Lakes School District is aiming for a LEED Silver rating under the Leadership in Environmental and Energy Design rating system administered by the U.S. Green Building Council.

"Everything we take out has to be recycled," said Superintendent Mark King, noting that the district also qualifies for additional state money by sticking to green building standards.

The Moon School District is also incorporating green principles into the design for its new high school, such as low-VOC (Volatile Organic Compounds) paint and glazing for the windows that virtually eliminates glare.

In addition to new buildings, several school districts -- including South Butler, Charleroi and Keystone Oaks -- switched to a four-day work week this summer to save energy. The change meant lower fuel costs for employees and lower operating costs for utilities such as air conditioning and electricity for school buildings.

South Butler also contracted with an energy management firm this year and is currently implementing new strategies for energy savings that don't require buying new equipment or making students uncomfortable, such as turning down the temperature on the hot water heater and turning off accent lights.

Other districts are reworking their traditional environmental programs, such as recycling. Penn Hills is looking at expanding its recycling program, pushed by a student representative on its school board. Currently, the district recycles printer cartridges and cell phones and offers Abitibi recycling bins for paper. It is considering adding glass and plastic to its recycling effort.

The Mt. Lebanon School District also expanded its recycling program last year as part of a student-led initiative.

The program worked so well that some elementary school students would jump to "recycle" poor scores on quizzes instead of taking them home to their parents, some teachers joked in the conference room this month.

"They really grasp hold of it big time," said Adam Humes, a third-grade teacher at Markham Elementary who said students sometimes booed classmates who threw away paper in the trash can rather than the recycling bin. "They take it such to heart."