PORTLAND – The terror attacks of Sept. 11, 2001, and a new climate of security consciousness since then have spawned a new homeland security industry in Maine.

New devices and products include sensors to detect chemical agents in the air, better airport screening devices, methods to allow easier tracking of what’s being shipped into the country, and high-tech methods to defend Navy ships from attacks.

The market for homeland security is big and likely to grow, according to Dawn Van Zant, president of ECON Investor Relations, which works with businesses involved in homeland security.

The budget for the new Department of Homeland Security is nearly $40 billion, but the total market is estimated at nearly $100 billion when spending by local and state governments and businesses are included, Van Zant said.

“There’s a huge market opportunity for those areas and the bigger defense companies might not be the ones to benefit,” she added.

New Maine security companies include Treadstone 71 of Scarborough, which specializes in securing companies’ ideas and plans.

Treadstone 71 President Jeff Bardin said his company is not worried so much about office locks or motion detectors.

“Much like there’s a hardening of physical structures, we’re hardening the information side of the house,” said Bardin. He declined to identify the firm’s clients, but said they include companies in Maine as well as others around the country.

Other Maine companies have been involved in anti-terrorism work since before it gained urgency.

Ten-year-old Sensor Research & Development of Orono, which works mostly on sensors that monitor air and water pollution, saw interest in its chemical and biological detectors rise sharply after 9-11.

The company is completing development of a sensor, about the size of a pager, under a contract with the Defense Department.

Detection Technologies of South Portland is developing detectors that can be used in airports or mounted in office corridors, in addition to hand-held units.

Technology Systems Inc. of Wiscasset is refining some of its products for the Navy to help defend ships against terrorism. An example is a monitor that combines an underwater camera with computerized navigation equipment.