The Environmental Protection Agency appears prepared to take the side of PVC manufacturers in a long-running debate on dioxin emissions. Industry officials say an EPA study is preparing to conclude that PVC manufacturing is not a significant source of dioxin emissions, and also that the agency seems ready to endorse industry arguments on incinerator emissions from PVC.
The agency plans to release its long-awaited reassessment of the cancer-causing chemical next month, but industry officials say leaked EPA reports and presentations indicate that agency attention is shifting to other sources, such as open burning and disposal of utility poles.
"We are an industry that has worked with EPA to understand and control dioxin," said Tim Burns, executive director of the Vinyl Institute in Arlington, Va. "Our study and analysis indicates we are a minor part of the dioxin situation."
Some environmental groups, however, said the report confirms the need to phase out PVC, because both its manufacture and burning in medical waste incinerators and other sources emits dioxin to the environment.
EPA officials declined to comment.
A May 1 draft of the report, posted on the Web site of the Center for Health, Environment and Justice in Falls Church, Va., at www.chej.org, said vinyl manufacturing releases about 12 grams of dioxin a year, less than one half of 1 percent of the total.
In comparison, a 1993 Greenpeace estimate put vinyl industry emissions at up to 565 grams a year, which would have made PVC a significant source.
Burns said EPA accepted industry studies for dioxin releases. EPA rated the studies as representative of the entire industry.
A potentially more significant dioxin source connected to PVC is medical waste incinerators, which EPA says is the second-largest source of dioxin in the United States. Such incinerators produce 480 grams a year, out of about 2,800 released to the environment annually.
Industry officials have said vinyl accounts for 75 percent of the chlorine in medical waste incinerators. The vinyl industry argues that incinerator design and operation governs dioxin releases.
The draft EPA report seems to agree: "The empirical evidence indicates that for commercial-scale incinerators, chlorine levels in feed are not the dominant controlling factor" for how much dioxin is produced, according to the draft EPA report.
"Important factors which can affect the rate of dioxin formation include the overall combustion efficiency, post-combustion flue gas temperatures and residence times, and the availability of surface catalytic sites to support dioxin synthesis," the report said.
EPA estimates new emissions rules for incinerators will reduce waste combustion emissions by 98 percent, and the agency believes it has addressed big industrial sources of dioxin.
A spokeswoman for Falls Church-based Health Care Without Harm, which urges hospitals to phase out PVC, said EPA's new pollution control standards depend on incinerators consistently working well.
"The rules ... presume that the medical waste incinerator or the garbage incinerator operate at peak efficiency," said Jackie Hunt Christensen.
She noted that EPA put its estimates of medical waste incineration emissions in its lowest category of certainty, indicating it has low confidence in that data.
Not using PVC would help reduce dioxin, she said. "If you don't need to burn it at all, let's do that rather than argue about what level of dioxin air emissions are acceptable."
Greenpeace Legislative Director Rick Hind said vinyl, over its lifetime, is responsible for significant dioxin emissions. For example, he said EPA's dioxin assessment ignores incinerator ash, which is sent to landfills.
Hind also was skeptical that incinerator emissions will drop as much as EPA expects.
"The real-world impact of emissions is much higher from all categories of incinerators," he said. "The ideal that somebody in Washington imagines in an [air quality] standard is wiped out by a few accidents."