BANGOR, Maine — Threats to the United States are sometimes made in people’s bathtubs or basements, according to members of the FBI who were in town Tuesday to educate the region’s emergency responders about how to identify potential dangers.

“The training assists first responders to identify hazards they may find during their usual duties,” Capt. Alexander Wild, medical operations officer for the 11th Weapons of Mass Destruction Civil Support Team in Waterville, said during a break in the two-day training at Eastern Maine Community College.

Areas of focus include “biological threats, explosive and toxic chemicals, drug lab identification, the emerging threat of agri-terrorism and lessons learned from the Boston bombing,” said Susan Faloon, spokeswoman for the Maine Emergency Management Agency, which hosted the event with the Maine Guard.

FBI educators spent Tuesday “breaking down the different threats … and what you might run across,” Maj. Nehemiah Nattress, deputy commander for the 11th Weapons of Mass Destruction Civil Support Team, said Tuesday.

Emergency responders are key to identifying emerging dangers to domestic security, he said.

“[With] hillbilly laboratories, it’s not like in ‘Breaking Bad’ with all the [laboratory] glass, it’s what you can get in Home Depot and Lowe’s,” Nattress said. “There is so many odd little materials that you might run across. It helps a lot if you know the ingredients and you can say, ‘That is not meth. They’re making explosives, and I need to back away.’”

There are ways to make chemical and biological threats that are like making “bathtub gin,” he said. And such simple methods have been used in domestic attacks.

For an example, Nattress cited the biological threat found in castor beans that contain the poison ricin. Ricin was extracted from the beans and used to taint letters that were sent in April 2013 to the president and a senator from Mississippi.

The poison is lethal in tiny doses if inhaled or ingested, and there is no antidote. Fortunately, the letters were intercepted before reaching their target.

Nattress also pointed out how fertilizer was used as a weapon in the April 1995 Oklahoma City bombing.

“There are fairly innocuous substances out there that can be made into weapons,” he said.

Emergency responders “may come across grains or materials, and they may not know what they are, [but] if they can look around and see the other precursors, they will know if it’s a clandestine lab,” Wild said.

“Fake” clandestine labs were set up in the back of the training area in Bangor, so the 200 or so firefighters, police officers, emergency medical technicians, law enforcement trainees, college and university security officers, teachers and hospital staff at the training session could see firsthand what to be on the lookout for. Attendees came from all over New England.

“They’re all taking away something different depending on their scope,” Wild said of attendees. “The police departments pretty much already know about meth labs, but they may not know as much about explosives.”

Hospital staff attended because “they also run their own decontamination … and they need to be aware of hazards and how to prepare,” Wild said.

The second part of the training was to make connections between the region’s emergency responders and the FBI who would partner together if a major emergency occurred or a weapon of mass destruction was discovered, according to Special Agent Chuck Cabral, the weapons of mass destruction coordinator for the FBI Boston Division.

“We all work together. Teamwork is our No. 1 initiative,” Cabral said. “We are educating these folks about what we have [for resources]. Now, they are capable of calling … and we can call in federal assistance free of charge, of course.”

What is different nowadays is that “you can go online and you can get step-by-step instructions to the process of how this stuff is made,” Nattress said.

“This is a real threat because, unfortunately, people are doing this in the United States,” he said. “The FBI wants this information out there to first responders to make them safe, and in turn, make us all safe.”