Dieldrin in our water: A silent threat to Guam’s Health

By Dr. Michael Cruz

As a surgeon who has devoted much of my career to breast oncologic surgery, I have stood beside hundreds of women and families facing one of life’s most difficult diagnoses — breast cancer.

My decision to specialize in this field was deeply personal. My own mother was diagnosed at an early age with aggressive Stage III breast cancer. She fought bravely and survived, reminding me — and all who knew her — that breast cancer is not automatically a death sentence.

Her experience is a message of hope: that with faith, perseverance, and access to quality care, survival is possible. Though she later passed away from a stroke, her courage continues to guide me and the patients I serve.

That hope runs through my family’s story. My younger sister and my mother-in-law are also breast cancer survivors, both examples of strength and grace in the face of adversity. Their resilience—and those of the many women I have had the privilege to treat—reminds me that early detection, awareness and environmental safety are just as vital as medical care itself.

That is why the recent revelations about dieldrin contamination in Guam’s northern water supply deeply concern me, not only as a physician, but as a son, a parent and a member of this community.

Dieldrin is a highly toxic pesticide, banned in the United States for decades because of its link to breast cancer, liver disease, neurological damage and immune dysfunction. Yet for over 10 years, it has been detected at unsafe levels in parts of our island’s drinking water system.

Even more troubling, the Guam Waterworks Authority has acknowledged that it failed to adequately inform the public about this ongoing contamination.

This is not merely an environmental issue; it is a public health crisis. Guam

already faces some of the highest breast cancer rates in the Pacific. While cancer is multifactorial, environmental exposures such as dieldrin cannot be ignored as possible contributors. Persistent organic pollutants and chemicals that remain in the environment and human tissue for decades are known endocrine disruptors, meaning they can interfere with hormones that influence cancer risk.

Every woman diagnosed, every family affected, deserves to know that their water—the most basic element of life—is safe.

As the adjutant general of the Guam National Guard, much of my focus has been on defending our island from external geopolitical threats, preparing for challenges that might come from beyond our shores. But we must also recognize the threats that lie within and around us—those that quietly infiltrate our soil, our water and, ultimately, our bodies. The very elements that should be sustaining and nourishing us may, without vigilance, become sources of harm.

As a physician and public servant, I believe we must insist on transparency, accountability and immediate action:

• Public release of all historical and current data on Dieldrin contamination levels and affected wells.

• ⁠Independent testing and health surveillance for residents in the northern districts.

• ⁠A comprehensive epidemiologic study to examine links between environmental toxins and Guam’s breast cancer rates.

• ⁠Assurance that safe, clean water is being provided to every household and school.

• This is not about blame. It is about responsibility — the collective duty to protect the health of our people today and generations to come.

When it comes to cancer, knowledge and prevention are everything. Hope begins with truth, and truth begins with transparency. The people of Guam deserve nothing less than full disclosure and decisive action to ensure their safety.

Let us not remain silent in the face of preventable harm. Let this be the moment we choose to confront the unseen threats in our environment—not with fear, but with courage, science and compassion.

Dr. Michael W. Cruz, MD, MBA, FACS, is a breast oncologic surgeon and the Adjutant General of the Guam National Guard. He previously served as Lieutenant Governor of Guam and has been a long-time advocate for cancer awareness, prevention, and the health and safety of the people of Guam and the region.

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