Blue-Green Algae Arrives Early in Putnam County

Blue-Green Algae Arrives Early in Putnam County

BREWSTER, NY— Algal blooms have arrived early in Putnam County lakes this year, due to the recent mild winter. So far this year, at least six beaches have been closed due to harmful growth. Algae can be more than a simple nuisance and may present a serious health hazard. Residents should be cautious when swimming, boating, or even just cooling off in waters with any algae.

“Blue-green algae present special problems,” explains Michael Nesheiwat, MD, Interim Commissioner of Health. “This type is a toxin-producing cyanobacteria, which if swallowed is harmful to humans and animals. At high levels, it can cause nausea, diarrhea and vomiting. It can also cause irritation of the skin, eyes, nose, throat, and respiratory tract.”

Some algae are harmless and in fact are an important part of the food web. However certain types grow quickly and form blooms, which can cover all or portions of a lake. Because it is hard to tell a harmful algal bloom from a harmless one, it is best to avoid swimming, boating or otherwise playing in or drinking water with a bloom.

Robert Morris, PE, MPH, director of environmental health at the Putnam County Department of Health (PCDOH), says, “To be safe residents should avoid contact with any water that has a floating covering or scum on its surface, is discolored or has an unpleasant odor. Blue-green algae can form a thick mat on the water surface resembling paint. It can also range in colors from green, blue, brown, yellow, grey, or even red. It has been a significant problem in Putnam County in recent years, as elsewhere.”

The Putnam County Department of Health (PCDOH) closely monitors permitted bathing beaches, performing periodic checks at regular weekly or biweekly intervals, depending on the situation. The PCDOH also responds to calls from town and village personnel. Town officials must close a beach when there is visible presence of blue-green algae and they work closely with the PCDOH to reopen the beach as soon as the bloom clears. This process was streamlined last year when the PCDOH began expedited, on-site testing at the main office. Previously, samples were sent to an outside lab and results could take three to four days.

While not all algal blooms are hazardous, the PCDOH recommends the following precautions for all of them:

  • Avoid or limit exposure to water when these algal blooms occur. Swimming, water-skiing, wading, playing by the water, etc., may cause accidental swallowing, skin exposure, or inhalation of airborne droplets. Use added caution with open cuts or sores.
  • Do not allow young children or pets to play in water where an algal bloom is present.
  • Wash hands and body thoroughly if any exposure occurs.
  • Do not use any water from lakes with algal blooms for drinking unless treated through a municipal water treatment plant.


There are water treatments to reduce the blooms in lakes but prevention is by far the best tactic. Treatments can involve the use of algaecides, but they have the same precautions as any pesticide.  Treatment methods, if any, are strictly a town decision, and application of an algaecide requires approval by the Department of Environmental Conservation (DEC).  Prevention involves community-wide efforts to reduce fertilizer use, keep septic systems running efficiently and manage storm water.

When the water clears, either naturally or by treatment, water testing must be conducted to ensure resident safety. Toxins can still be present even after the bloom looks like it has passed. Only after a satisfactory result on a water test can town personnel re-open the beach.

The Health Department’s mission is to improve and protect the health of the Putnam County community, composed of nearly 100,000 residents. Core services include community health assessment, disease surveillance and control, emergency preparedness, environmental health protection, family health promotion and health education. For more information, please visit the PCDOH website at or visit the social media sites on Facebook at and Twitter @PutnamHealthNY.  # # #