in Honor of 'Earth Day'

In 1971 an environmental and antiwar ethic was taking root in Canada, and I chose to participate. As I completed a Ph.D. in ecology, I combined my science background with the strong media skills of my colleagues. In keeping with our pacifist views, we started Greenpeace.

But I later learned that the environmental movement is not always guided by science. As we celebrate Earth Day today, this is a good lesson to keep in mind.

At first, many of the causes we championed, such as opposition to nuclear testing and protection of whales, stemmed from our scientific knowledge of nuclear physics and marine biology. But after six years as one of five directors of Greenpeace International, I observed that none of my fellow directors had any formal science education. They were either political activists or environmental entrepreneurs. Ultimately, a trend toward abandoning scientific objectivity in favor of political agendas forced me to leave Greenpeace in 1986.

The breaking point was a Greenpeace decision to support a world-wide ban on chlorine. Science shows that adding chlorine to drinking water was the biggest advance in the history of public health, virtually eradicating water-borne diseases such as cholera. And the majority of our pharmaceuticals are based on chlorine chemistry. Simply put, chlorine is essential for our health.

My former colleagues ignored science and supported the ban, forcing my departure. Despite science concluding no known health risks – and ample benefits – from chlorine in drinking water, Greenpeace and other environmental groups have opposed its use for more than 20 years.

Opposition to the use of chemicals such as chlorine is part of a broader hostility to the use of industrial chemicals. Rachel Carson's 1962 book, "Silent Spring," had a significant impact on many pioneers of the green movement. The book raised concerns, many rooted in science, about the risks and negative environmental impact associated with the overuse of chemicals. But the initial healthy skepticism hardened into a mindset that treats virtually all industrial use of chemicals with suspicion.

Sadly, Greenpeace has evolved into an organization of extremism and politically motivated agendas. Its antichlorination campaign failed, only to be followed by a campaign against polyvinyl chloride.

Greenpeace now has a new target called phthalates (pronounced thal-ates). These are chemical compounds that make plastics flexible. They are found in everything from hospital equipment such as IV bags and tubes, to children's toys and shower curtains. They are among the most practical chemical compounds in existence.

Phthalates are the new bogeyman. These chemicals make easy targets since they are hard to understand and difficult to pronounce. Commonly used phthalates, such as diisononyl phthalate (DINP), have been used in everyday products for decades with no evidence of human harm. DINP is the primary plasticizer used in toys. It has been tested by multiple government and independent evaluators, and found to be safe.

Despite this, a political campaign that rejects science is pressuring companies and the public to reject the use of DINP. Retailers such as Wal-Mart and Toys "R" Us are switching to phthalate-free products to avoid public pressure.

It may be tempting to take this path of least resistance, but at what cost? None of the potential replacement chemicals have been tested and found safe to the degree that DINP has. The Consumer Product Safety Commission recently cautioned, "If DINP is to be replaced in children's products . . . the potential risks of substitutes must be considered. Weaker or more brittle plastics might break and result in a choking hazard. Other plasticizers might not be as well studied as DINP."

The hysteria over DINP began in Europe and Israel, both of which instituted bans. Yet earlier this year, Israel realized the error of putting politics before science, and reinstated DINP.

The European Union banned the use of phthalates in toys prior to completion of a comprehensive risk assessment on DINP. That assessment ultimately concluded that the use of DINP in infant toys poses no measurable risk.

The antiphthalate activists are running a campaign of fear to implement their political agenda. They have seen success in California, with a state ban on the use of phthalates in infant products, and are pushing for a national ban. This fear campaign merely distracts the public from real environmental threats.

We all have a responsibility to be environmental stewards. But that stewardship requires that science, not political agendas, drive our public policy.

Mr. Moore, co-founder and former leader of Greenpeace, is chairman and chief scientist of Greenspirit Strategies.