WASHINGTON — If anyone tried to deploy a “dirty bomb” or other radiological weapon in the D.C. region, Metro Transit Police officers might be the first line of defense, and Thursday, the Metro Board is expected to formally accept radiation detection devices purchased for each member of the police department.

The transit police officers play a critical role in efforts to reduce the risk of a radiological terror attack because of the large area the agency covers, briefing documents for the Metro Board said.

The devices were purchased through a federal Homeland Security grant.

“The MTPD role in regional operation plans is to successfully prevent, deter, detect, and interdict the illicit use, storage, or transportation of radiological/nuclear material that could be used to attack WMATA or other critical infrastructure in the (National Capital Region),” the documents said.

The Metropolitan Washington Council of Governments used $2.4 million in federal grant funding to buy 375 personal radiation detectors for transit police officers, plus more than 80 specialized devices for use by special teams or in special circumstances. Those specialized devices include 10 portable systems that can be used at security checkpoints and 11 devices that identify the type of isotope emitting the detected radiation.

Metro Transit Police plan to train all officers on how to use the personal detection equipment, and about 60 officers will be trained on how to use the specialized devices that can be used either for incidents in the Metro system or anywhere else in the region.

Officers will carry the personal detection devices daily as part of the regular gear. The devices last five to seven years.