BOSTON —Patrolling the streets of Baghdad, Brian Tivnan admits that he was a menace.

"Painkillers. Morphine. Heroin," he said. "Any opiate substance I could get my hands on, I would use it."

Tivnan, now back in Massachusetts, was a menace to himself and his fellow soldiers because of his addiction.

"I was 100 percent a danger to everybody and everything around me," he said.

Once proud to wear his country's uniform, Tivnaan became ashamed of the soldier he had become.

"Absolutely," Tivnan told News Center 5's Kathy Curran. "That's guilt and shame I'll live with for the rest of my life, but today I can't allow it to consume me.

"I look back now I say, ‘How could I have been so irresponsible?' I had multiple people who I was in charge of, took their lives in my hands daily and I was a complete nightmare, complete mess."

Tivnan has battled addiction for much of his life. In 2007, when his National Guard regiment was sent to Iraq, he found when it came to being addicted to drugs while on active duty, he wasn't alone.

"It's a lot bigger than people think," he said. "You don't want to feel fear all day long, you don't want to feel depressed all day long, so if you find a substance or a way to take all that away, it just makes it all that much easier to do."

When Tivnan came home after his deployment, his heroin addiction spiraled out of control. He hit rock bottom, sleeping on the Greenway in Boston. He was in and out of treatment dozens of times and was revived with Narcan twice.

"I was in a basement of a house, and the last thing I really remember was I remember getting high, taking a few steps forward and there was a flat-screen TV that I fell headfirst through," Tivnan said. "I remember coming to with my brother kneeling on my chest. He had just given me Narcan and he was screaming my name."

Now Tivnan spends his spare time doing outreach on addiction, speaking out in a YouTube video to support Narcan and telling the story of his daily battle with addiction. He has been clean for more than two years.

"I've done some pretty difficult things, but making the decision to change your life in that way is one of the scariest things you can think of," Tivnan said.

Tivnan has likely saved others by using Narcan, but he also counts about 15 friends whom he's buried after overdosing, including the brother who saved his life.

Syphilis cases are on the rise in the U.S. military, where a 53 percent hike in infections constitutes a growing public health concern.

The increase, which coincides with similar trends in the civilian population, suggests troops are engaging in riskier sexual behavior, such as casual encounters fueled by the rise of Internet dating, the Armed Forces Health Surveillance Center said in a monthly report on communicable diseases.

"The increasing incidence of syphilis in military members is of significant public health concern because this finding suggests that some service members have been engaging in unsafe sexual practices that increase the likelihood of acquisition of other sexually transmitted infections," including HIV, the report said.

Between January 2010 and August 2015, 2,976 cases of syphilis were diagnosed in the armed forces, according to the report. Rates increased from 30.9 cases per 100,000 troops in 2010 to 47.4 cases per 100,000 in 2015. Men accounted for 88.7 percent of the cases. Rates of syphilis were highest among black, non-Hispanic servicemembers or those ages 20-29.

Since 2012, rates have also risen among other groups, including white and Hispanic troops. Of those infected, about 25 percent, or 727 cases, were also diagnosed with HIV.

Within the past month alone, the Army reported eight new cases of syphilis, the Navy six, the Air Force four, and the Marines one, according to a separate report, the Armed Forces Communicable Disease Weekly Report.

The overall increase demands a coordinated military response, according to the monthly report.

"Developing and implementing syphilis-prevention measures targeting service members at high risk of acquisition should continue to be promoted as well as continuation of aggressive sexual-partner notification programs," that report said.

Public-awareness campaigns related to sexually transmitted diseases have long been part of the military, dating back to World War II, when black-and-white service announcements warned of the perils of risky sexual behavior.

Increasing rates of syphilis in active-component servicemembers reflect similar trends reported in the U.S. civilian population, the monthly report said. In recent years, health officials have offered numerous reasons for a resurgence of syphilis, such as a decrease in safe-sex practices, an increased use of Internet casual-dating sites, and an increase in oral sex, which decreases the risk of HIV transmission but increases the risk of contracting syphilis.

It might be the world's most expensive gas station — not to mention a gross misuse of taxpayer money, according to a top government watchdog.

The Department of Defense spent $43 million to build a gas station in Afghanistan that should have cost roughly $500,000, the lead oversight team monitoring U.S. spending in Afghanistan has found. The discovery came as part of a broader investigation into allegations of criminal activity within the DOD's premiere program to kick-start the Afghan economy.

"It's fright-night at the Pentagon," John Sopko, special inspector general for Afghanistan reconstruction (SIGAR), told FoxNews.com, calling the spending "outrageous to the taxpayer."

At issue is spending by the Task Force for Stability and Business Operations, known as TFBSO or the Task Force, which ended in March 2015. But most alarming, according to Sopko, is the DOD's failure to answer questions about the $800 million program and its claim the Task Force's employees no longer work for the DOD.

"I have never in my lifetime seen the Department of Defense or any government agency clam up and claim they don't know anything about a program," said Sopko, a former federal prosecutor appointed by President Obama in 2012 to watch over spending in Afghanistan.