CLEVELAND — While the general vinyl industry is marshaling its forces to respond to the dioxin issue, suppliers and processors of flexible PVC could be dealing with even more questions.
That's because environmental concerns have been raised about each of the four major chemical components of flexible vinyl: PVC resins, phthalate ester plasticizers, stabilizers that often contain ``heavy'' metals, and pigments that include lead chromate pigments.
Industry representatives discussed those concerns, and the industry's responses, at an April 29 environmental seminar sponsored by the Chemical Fabrics and Film Association in Cleveland.
The PVC/dioxin issue is being overblown by Greenpeace, which is using less-than-accurate science, charged Ron McCreedy, a scientist with Dow Chemical Co. in Midland, Mich. McCreedy heads the Vinyl Institute's dioxin characterization program — a study that is trying to quantify the amount of dioxins released into the environment during the life cycle of vinyl products.
Even using the term dioxin can be misleading. McCreedy said at least 210 types of dioxin exist, but only 17 are considered cancer-causing by the Environmental Protection Agency.
When industry talks about dioxins, it is talking about the short list, while environmentalists often talk about all dioxins, McCreedy said.
And of the 17 dioxins on the EPA's list, each have been assigned a different level of toxicity as expressed in toxic equivalency.
Industry figures on dioxin amounts will include toxicity factors, giving a lower result than if all dioxins are measured equally, McCreedy said.
But Rick Hind, legislative director for Greenpeace's Washington-based toxins campaign, said in a telephone interview that the group uses both dioxin totals and toxic equivalency when calculating dioxin levels.
Portions of the Vinyl Institute's characterization study currently are undergoing independent peer review, McCreedy said.
So far the study has found ``very little or no'' dioxin emissions in products and waste that ``break the boundary'' of producers' plants.
Depending on a few statistical assumptions, the industry's studies indicate that the industry's total annual release of toxic dioxins amounts to 11/2-7 grams nationwide in the four types of PVC resins made, and treated waste water from PVC plants.
Phthalate esters, the additives that make vinyl flexible, have been linked in some literature to endocrine disruption — a broad term that covers disorders in the reproductive process of humans and animals.
``Phthalates are going to continue to be scrutinized,'' said John Bankston, product regulation supervisor for Aristech Chemical Corp. in Pittsburgh. ``Anyone can make an allegation, but it's another thing to back that allegation up with data.''
Meanwhile, Dean Finney, product stewardship manager for Eastman Chemical Co. in Kingsport, Tenn., provided some information of his own at the meeting.
Finney said the book Our Stolen Future, one of the original sources for the endocrine disruption debate, is ``a little science mixed with a great leap of faith.''
The book, by environmentalists Theo Colborn and John Myers and journalist Diane Dumanoski, asserts that some chemicals, including phthalate esters, disrupt the endocrine system by mimicking certain hormones in animals.
Finney cited examples in the wild where accidental spills led to reproductive problems in wildlife, but said evidence does not support that general environmental levels of the chemicals have led to problems.
Finney also said the data linking phthalate esters to endocrine disruption is inconclusive.
Lead chromates are used in the vinyl industry as pigments, especially red, orange and yellow shades, according to Bruce Berman of Penn Color Inc., a company that sells pigments.
Lead chromates are regulated along with pure lead, even though as compounds they do not present the same level of hazard, Berman said.
Regulations require workers to use special protective gear, and rigorous cleaning procedures must be followed in plants using the pigments in dust form. Since the regulations took effect, sales of lead chromate pigments have been halved, he said.
The alternatives to lead chromates can be five times as expensive, he said.
A less-expensive way for processors to handle lead chromates is to buy the pigments in a ``capsulized'' dispersion form premixed with PVC resins and plasticizers. That approach allows processors to let ``someone else go through the hassles and machinations'' of lead abatement, Berman said.
Berman said environmental and occupational concerns about heavy metals are unlikely to subside, so organic-based pigments are being developed and improved.
``However, as you probably know, none of these pigments are `drop-ins,' and none possess all the positive qualities'' of lead chromates, Berman said.
Stabilizers used to prevent the degradation of vinyl products also include heavy metals, all of which have come under some form of environmental scrutiny, said Victor R. Struber, director of new business development for Witco Corp. of Greenwich, Conn.
But that scrutiny is not always founded in good science, according to Struber.
``The attack on additives was initiated by groups that would rather see the industry's demise than a rational approach to the issue,'' he said, adding that much of the varied state and federal regulatory structure was inspired by the ``hysteria'' surrounding media stories about lead poisoning in children who ate paint chips.
``Lead and cadmium are considered much more toxic than arsenic'' by the EPA, he said. ``Go figure.''
But Struber still advocates using alternatives to heavy metals in stabilizers.
``There are replacements for the `real bad' [additives] for PVC applications,'' he said in a phone interview after the conference, noting that Witco stopped producing additives that contain cadmium.
``Don't bring any more adverse publicity to the finished PVC article,'' Struber said. ``As long as there are viable substitutes, let's put our energies into developing those substitutes instead of digging in our heels and fighting the regulators,'' he added.