LITHIA — The illness hit Marine Corps Sgt. Maj. William A. Hines in 2010 like no enemy he had ever experienced.

Assigned to the 4th Assault Amphibian Battalion headquarters in Tampa, Hines went on a 4-mile run, something he had done hundreds of times in more than two decades as a Marine. But afterward, he couldn't catch his breath. He felt pressure on his head and couldn't focus.

Another Marine rushed Hines to Tampa General Hospital, where doctors would ultimately find blood clots in his lungs.

"They were amazed that I was still alive," Hines said.

In the four years since, the 46-year-old Lithia resident's health has steadily worsened, though his doctors are unsure why. Hines, who achieved the highest noncommissioned rank in the service, was forced to retire in 2013 after 27 years in the Corps. Once a model of fitness, he's now too sick to work. In fact, Hines said, he is often too weak to walk his dogs.

The cause, Hines believes, is something the government gave him to protect him from biological warfare — the anthrax vaccine.

The Pentagon maintains that the vaccine provided to more than 3 million troops since 1998 is safe and effective. But some veterans of Iraq and Afghanistan have persistently questioned whether a range of puzzling health ills they have suffered might be linked to the vaccine.

Hines, who will be on blood thinners the rest of his life, has spent much of the past four years researching the vaccine and networking with other ill veterans. And he has helped create an informational website, veteranarchangel.com.

"There are a lot of people just like me who are sick," Hines said. "We're broken, and we want to know how to get ourselves fixed. We want answers. But we haven't gotten any."

Military health and Marine Corps officials could not be reached for comment during the holiday week.

"The safety and efficacy of the vaccine has been well-documented, and this nation owes its service members that are going into harm's way the best possible protection this country can afford them to be able to operate in any number of environments," a Pentagon spokesman told CNN in 2008.

But some investigative reports have suggested the vaccine triggered a series of adverse autoimmune reactions and diseases, from lupus to aching joints and chronic pain. Such symptoms are often lumped together as Gulf War syndrome.

In the book Vaccine A, journalist Gary Matsumoto argues that the government spiked the anthrax vaccine with a booster called squalene to make it more effective. But this booster sickened veterans by causing a supercharged reaction in immune system, the book said.

The Pentagon denies adding squalene, though it acknowledged that some lots of the vaccine may have been contaminated with trace amounts of the additive that it claimed were harmless.

Tulane University researchers found squalene antibodies in the blood of sick veterans it tested, including those who received the same vaccine lot as Hines did in 2003.

That year, Hines said, he became acutely ill in Kuwait after receiving the vaccine in the states. He suffered vomiting, diarrhea, fever and fatigue over the course of several weeks. He said he was almost sent back home, but eventually recovered.

He thought little of the incident until he became very ill in 2010.

After he was rushed to TGH in 2010, Hines said his wife, Janine, found Vaccine A and was startled to see the book describing how others who received the vaccine had suffered some of the same symptoms as her husband.

"It just nailed everything that happened to me," Hines said.

A test to detect squalene antibodies in the blood of those who received the vaccine has been developed but is not available, something that especially angers Hines. He said the test would help link symptoms to squalene, or even rule it out.

Hines said he has been frustrated by his inability to get Marine Corps leadership to answer basic questions about the vaccine.

"It's pretty disappointing," he said. "I think my family deserves an answer."

He said doctors he has seen through Tricare, the military health system, treat the symptoms and are reluctant to discuss causation.

Hines said he suffers from frequent pain, severe fatigue, aching joints, headaches and is easily winded. The severity of the symptoms has worsened in the past six months, he said.

"I wake up every morning and feel like I am extremely hung over," Hines said.

Hines' close friend, Tampa attorney James Hines, who is not related to the Marine, said he has been startled by his friend's physical decline.

"We used to run seven-minute miles together," James Hines said. "Now this guy can't walk up the stairs without having a hard time. All of a sudden he's fallen off a cliff. I'm afraid he's dying."

Hines visited a Mayo Clinic facility in Jacksonville this month for a week of tests and meetings with specialists. He returns in January. So far, doctors have diagnosed him with fibromyalgia, an ailment of unknown origin that causes widespread pain.

A sergeant major is usually the person in the Marine Corps responsible for the well-being and morale of the troops. Hines still feels that responsibility extending beyond retirement. He wants to be able to get answers for other Marines who also are sick.

"It's my responsibility," Hines said. "Marines take care of their own."

Contact William R. Levesque at levesque@tampabay.com or (813) 226-3432.

The following statement was sent to the Tampa Bay Times by the Pentagon after publication of the story:

"The anthrax vaccine has been licensed and safely administered in the U.S. since 1970. It is required for service members deploying to U.S. Central Command or the Korean Peninsula for 15 or more consecutive days, as well as certain other designated units. Since 1998, more than three million service members have received the vaccine, and 12.7 million total doses have been administered. There are no known long-term side effects to anthrax vaccine. Like all prescription drugs, there are some side effects to being vaccinated, such as soreness, redness, itching, swelling, and lumps at the injection site. These symptoms usually go away after a few days. Like all vaccines, most adverse events are minor and temporary. Serious events, such as those requiring hospitalization, are rare. They happen about once per 200,000 doses. Severe allergic reactions can occur after any vaccination, less than once per 100,000 doses. Anthrax vaccine has a safety profile equivalent to that of other routinely used vaccines.

In addition to this statement, you can find more information at www.vaccines.mil/anthrax, or through the CDC's website at www.cdc.gov/anthrax."