The Massachusetts Department of Public Health has warned the NECC multiple times since 2002 about unsanitary conditions at its facility.

Statutory and regulatory requirements stipulate that compounding can be done only on receipt of a patient-specific prescription, Dr. Madeleine Biondolillo, director of the department's Bureau of Healthcare Safety and Quality, told reporters Wednesday.

Asked if there had been a violation, she said some organizations may have operated contrary to the licensing regulations, but that is part of the investigation.

Compounding pharmacies were originally created for doctors or pharmacists to make small amounts of custom medications -- for example, adding flavored syrup to a cough medicine, or creating a smaller dose for an individual patient if it's not created commercially.

They've grown into a much larger business. Pharmacy compounding accounts for 37 million prescription drugs in the United States each year.

Some compounders ship thousands of custom drugs all over the country. NECC is licensed to distribute to surgery centers and pain clinics in 50 states.

Nearly 10% of drugs administered in the United States come from compound pharmacies, according to a 2003 Government Accountability Office report.

Meningitis is an inflammation of the protective membranes covering the brain and spinal cord. It is usually caused by an infection, frequently with bacteria or a virus, but it can also be caused by less common pathogens, such as fungi in this case, according to the CDC.

Fungal meningitis is very rare and, unlike viral and bacterial meningitis, is not contagious.

Dr. William Schaffner, chairman of the Department of Preventive Medicine at Vanderbilt University Medical Center, told CNN that fungal infections are not usually mild. He said when a fungus invades small blood vessels, it can cause them to clot or bleed, which can lead to symptoms of small strokes.

In addition to typical meningitis symptoms like headache, fever, nausea and stiffness of the neck, people with fungal meningitis may also experience confusion, dizziness and discomfort from bright lights. Patients might just have one or two of these symptoms, the CDC says.

Health officials say any patients who received an injection at one of the facilities beginning May 21 and who began showing symptoms between one and three weeks after being injected should see their doctor right away.

The earlier a patient gets treatment, the more likely he or she will survive.

Patients are treated with anti-fungal medication, which is given intravenously, so patients have to be admitted to the hospital, the CDC said. Patients may need to be treated for months.

The FDA is urging anyone who has experienced problems following an injection with the NECC product to report it to MedWatch, the FDA's voluntary reporting program, by phone at 1-800-FDA-1088 or online at www.fda.gov/medwatch/report.htm.