To guard her cat, Hobo, against fleas, Sue Eisenfeld had her home sprayed with a pesticide. Within a day, she was having health problems. (Dayna Smith/FOR THE WASHINGTON POST)

Last winter, despite a low-level warning beacon in my gut, I hired a company to apply a chemical flea treatment in our house. Not wanting to waste time on home remedies that might not work, I thought, “Let’s just get it over with.”

I made this decision even though I’d been a “ban lawn-care pesticides from our campus” activist in college and had spent nearly my entire professional life as a communications consultant to the Environmental Protection Agency, writing materials for the public about environmentally sound behavior.

As an environmentalist, I am an organic vegetarian. I avoid processed foods with ingredient names I can’t pronounce, use reusable tote bags, avidly recycle and drive a low-emissions car.

Yet, on the eve of my decision, I looked at my poor kitty. Despite applications of topical anti-flea drops, he’d been licking himself raw during the past four months. I had to take some kind of action, and fast.

The treatment seemed reasonable: An aerosol flea spray would be applied directly to the floor; it wasn’t some kind of flea bomb or fogger. I assumed that if there were risks or warnings or precautions I should know about, the pest control company, which we’d used to treat the exterior of our house against ants, would tell me. I decided to trust “the system” — which, I reasoned, was created to protect consumers, after all.

The next morning a man came to our house with two aerosol cans of a pesticide and targeted our hardwood floors and rugs, as well as the concrete floor in the basement. The pesticide — in the form of a mist designed to fall quickly to the floor — contained chemicals to kill insects and interrupt the life cycle of fleas.

The technician didn’t provide any instructions other than to take the cat and stay out of the house for three to four hours until the product had dried.

Six hours later, my husband and I returned home and found big wet drops all over the floors. When we called the pest control company, the manager was perplexed. He recommended that we mop up the residue, then throw away the sponge.

While my husband did the mopping, I wrote an instant message to a friend: “This is a disaster,” I typed. “Don’t worry about it,” he wrote back. “It’s no big deal.”

Strange symptoms

The next morning, I awoke to a headache in the back right quadrant of my skull. I felt a bit woozy and off balance and figured I was coming down with a cold. By evening, my arms were buzzing with an odd, electric energy. My husband and my cat were fine.

The next day, my left arm and leg felt icy hot. And my torso reacted to cold as if it were being stung by yellow jackets.

In another 24 hours, my fatigue was so intense that even if the house had been on fire, I couldn’t have peeled myself out of bed. A day later, my right side lost much of its strength. I struggled to brush my teeth, write, type and lift a fork. Standing up in the shower and lathering my hair became things I could no longer do at once.

Two trips to the emergency room ruled out a stroke and a brain tumor. But an MRI scan showed a lesion on the spinal cord in my neck. This scar or defect, I was told, had chewed away some of the protective myelin that coats nerves and transmits messages in the nervous system. This damage was scrambling messages being sent throughout my body about temperature and pain and strength and balance.

Process of elimination

A week after my symptoms began, a neurologist diagnosed the problem as transverse myelitis, an inflammation of the spinal cord. Until my spinal tap and blood test results came back, he couldn’t tell me the cause.

Transverse myelitis can be the result of a viral infection such as chickenpox, shingles, herpes, flu, HIV, hepatitis A or rubella. It can also be caused by abnormal immune system reactions, and it’s sometimes a complication of syphilis, measles or Lyme disease.

The neurologist said my symptoms could also be caused by multiple sclerosis, lupus, thyroid disorder, tuberculosis or other diseases.

“What about pesticide exposure?” I asked.

My doctor listened to the story of the chemical flea treatment and the coincidental timing of the onset of symptoms, and then rushed out of the room to call the manufacturer of the chemical spray. When he came back, he reported that the company’s medical staff said no one there had heard that their product had caused such symptoms.

“It’s concerning, however,” my doctor said. “And I sure wouldn’t use that stuff myself.”

He put me on a megadose of intravenous steroids for five days, then steroid pills for a week. My icy-hot sensation began to fade, and my strength began to return, although a full recovery took several months.

Soon my test results started streaming in. Lyme disease: negative. Lupus: negative. Meningitis: negative. Tuberculosis: negative. Cancer cells: negative. But four tests involving the cerebrospinal fluid that are often used as indicators of multiple sclerosis came up positive — stunningly unpleasant news that made my mind swirl.

“We can’t know for sure about multiple sclerosis,” my neurologist explained, “until you get a follow-up MRI in four to five months, to see whether the lesion is still there or if there are any new ones.” A definitive diagnosis, he explained, requires either two “episodes” like the one I had experienced, or two or more lesions on the spinal cord. I would now just have to wait.

Seeking information

My recovery involved physical therapy, occupational therapy, exercise and rest. My mental recuperation required research. I wanted to know more about this pesticide.

First I found the pesticide label online, with its information about using the product properly. What this told me was that the technician had not given me enough information. The label instructs users to cover all food-processing surfaces, utensils and exposed food prior to spraying. We hadn’t been told to do anything like that — to remove the dishes sitting out on our drying rack, to cover our cutting board or the fruit and vegetables on our counter.

The label directs pesticide applicators to avoid thoroughly wetting the surfaces being sprayed. Yet there had been those drops on the floor six hours later. It also says that the sprayed area should be ventilated after treatment. News to us.

I then contacted the pest control company and the manufacturer to report the incident. The pest control company said that an experienced technician had done the work. The manufacturer declared that information about any reports of health effects was proprietary.

So I filed a Freedom of Information Act request with the EPA, the federal agency responsible for regulating pesticides. Although incident reports made to the manufacturer may be considered proprietary, the manufacturer must give them to the EPA, which also collects incident reports from the public and from other government agencies and nongovernmental organizations.

A few weeks later, I got my response: an 82-page report from the EPA that made it clear to me that MS wasn’t the cause of my symptoms. The report showed that from 1992 until early 2010, 156 “minor” human incidents had been reported to the agency concerning the product used in our house, as well as 24 “moderate” and 515 “major” human incidents.

Among the complaints in the moderate and major medical incidents were dizziness, difficulty breathing, difficulty swallowing, muscle weakness, tremors, abdominal pain, disorientation, stumbling, coma, seizure, liver failure, lethargy, numbness, blurred vision, chills, blood in the urine, memory loss, migraines, inability to walk and heart attack.

A second FOIA request about three of the active ingredients in “my” pesticide revealed that thousands of medical complaints had been filed about these chemicals when they were used in other pesticide products.

Four months after my neurological episode, when I was finally able to walk in a straight line and not have my right hand buzz every time I bent my head toward my chest, I had another MRI. As I had expected — after weeks of follow-up neurological studies, blood tests and second opinions — the possible MS diagnosis was thrown out. My spinal cord lesion — attributed to, as my neurologist put it, “an autoimmune response to pesticide exposure” — had vanished.

At home, I threw away our conventional cleaning products and purchased all-natural cleaners. I canceled our quarterly outdoor pesticide treatment against ants. I bought essential-oil bug spray for summertime mosquitoes. I returned to working on the book I had just started to write and the new career I had launched.

I could have left it at that: gratitude, a new beginning, a renewed commitment to health. But I knew something more needed to be done to prevent incidents like mine — or worse — from happening to others. So here’s what I learned:

Consumers must receive more information about the pesticides being used in their homes. And they need regulatory backup protection.

If the company I dealt with had been required by law to show me the label information or read it to me aloud like a Miranda warning, I would have put away the apples and tomatoes, covered the cutting board and dishes, and, later, opened the windows and set up fans.

Similarly, if, before treating my house, the pest company had been required to provide me with the EPA’s Citizen’s Guide to Pest Control and Pesticide Safety — much as contractors, home sellers and landlords are required to give occupants certain brochures about the hazards of lead-based paint — I might have been encouraged to evaluate less-toxic alternatives or ask more questions.

If the label information had provided directions for contacting my state pesticide regulatory agency to report misuse or problems, I might have called soon after my problems surfaced. The agency could have sent an investigator to my house in Virginia to collect evidence to determine if the pest control company had broken any laws.

Finding pesticide residues on a food preparation surface or on a cat’s water bowl “would hang an applicator,” one state investigator told me. Not obeying the label instructions is a violation of federal and state law, and in Virginia, the company could be fined up to $5,000 for this violation, a penalty that could motivate it to train its technicians better and provide homeowners with more information.

Beyond that, it’s time to improve the system for regulating pesticides. Congress and other policymakers should reform the Federal Insecticide, Fungicide, and Rodenticide Act of 1947 and the EPA regulations that implement it. Pesticide manufacturers, in performing mandatory safety studies before their products are allowed on the market, should be required to test the combined effects of multiple pesticides and the effects of their pesticides combined with chemicals that people are exposed to each day, such as plastics and drugs.

Manufacturers should also be required to tell the EPA and consumers what the “inert” or “other” ingredients are that can make up 95 percent of a pesticide product: Some of these substan-ces can be even more toxic than the active ingredients.

The federal pesticide law or EPA needs to better define what kinds of detrimental effects are unreasonable for people to suffer. Currently, if a pesticide performs its intended function without “unreasonable adverse effects” to human health or the environment when used according to label instructions, it is allowed on the market. But the law never defines “unreasonable.” It says only that to determine “unreason­able risk,” EPA must take into ac­count “the economic, social, and envi­ronmental costs and benefits.”

Finally, EPA should be required to assess whether any “green” products can achieve the same results as pesticides, with less risk. The federal law should require an assessment of such alternatives as part of the pesticide approval process, eventually restricting the use of certain chemicals as safer approaches and technologies become available. This idea would be a new way of thinking, but it is time for the outdated regulatory approach to pesticides to move into the future.

My decision to use a chemical pesticide in my home was a moment of weakness, a test of blind faith in a system that was supposed to protect me from harm. No one knows why I was affected and others in my household weren’t. Thankfully, I am completely recovered.

Yet, the desire for quick, no-fuss ways to get rid of bugs will never fade. Without additional protections, unwary consumers will continue to turn to chemical products they assume are safe. They will find that they may be protected from bugs — but not from harm.

Eisenfeld is a writer and editor in the Washington area. This article was excerpted from the May issue of Health Affairs and can be read in full online at