Millions of pounds of toxic chemicals still pour into the air annually from Houston-area industries, 16 years after Congress declared war on air pollution with sweeping changes to the Clean Air Act.

These routine releases include hundreds of tons of substances that may cause cancer. Some of the chemicals also could kill or injure a person immediately if they escaped accidentally.

An Environmental Protection Agency study two years ago said toxic chemicals are a bigger health threat in the air than in water or at hazardous waste sites, but the problem was mired in obscurity until December, 1984.

Then, in Bhopal , India, poisonous gas killed more than 2,000 people and injured thousands, transforming toxic air pollution into a major environmental issue of the 1980s.

The Bhopal disaster sparked new concerns about the complex problem. Last year, EPA proposed two plans - one for responding to accidents posing immediate danger, another for reducing the leaks and routine releases that may cause cancer and other long-term ailments.

Controversy surrounds both plans. The debate has profound implications for the Houston area, whose sprawling petrochemical complex is the world's largest. An examination of the issue by the Houston Chronicle shows:

Industrial discharges of toxic chemicals in five counties on the upper Texas coast - Harris, Galveston, Brazoria, Jefferson and Orange - rank among the nation's largest.

Regulations have forced industry to make substantial reductions in air pollution from a broad group of chemicals that includes many suspected cancer-causing agents and other toxic substances. But the Texas Air Control Board says plants in the five counties stll release more than half a billion pounds of these "volatile organic compounds" annually.

Leading scientists say most chemicals probably do not cause cancer, but eight of 10 chemicals have never been tested or studied enough to make a judgment about longterm health risks.

Twenty-nine companies in the five counties told a House subcommittee their plants released or had permits to release about 10 million pounds of specific toxic substances in 1984.

An EPA study said toxic chemicals in the air cause 1,300 to 1,700 cancer cases a year nationwide. Most are caused by small sources like gasoline stations and wood stoves, it said, but people living near large chemical plants have much higher individual risks.

More than 12,000 accidental releases of toxic chemicals and other air pollutants - or plant conditions with the potential for that to happen - were reported to the state by companies in the five counties since 1980.

Regulations allow a hodgepodge of safeguards - sometimes differing for the same chemical at two units of the same plant - but company and government officials say a catastrophic release is unlikely because of the chemical industry's good safety record.

An EPA-commissioned study last year compiled a partial listingof toxic chemical accidents since 1980 in selected areas, including Texas. There were at least 6,928 such accidents that killed 130 peopleand injured 1,478.

To prepare for immediately dangerous leaks, EPA has developed a significant new program to give state and local officials guidance, EPA Administrator Lee Thomas said. But critics say it does nothing torequire industry to prevent accidents.

To combat cancer and other chronic risks, EPA is boosting its effort to set regulations for more chemicals than the very limited" number with controls so far, Thomas said. But critics say EPA's regulation-setting process weakens protection of public health. And state officials in Texas and elsewhere doubt they can handle new duties required by the EPA plan.

The debate is complicated because government agencies know relatively little about toxic air pollution - specific chemicals released, volumes and long-term hazards.

All air pollutants are toxic" by definition, but that term is widely used to designate substances that may pose immediate or chronic risks - sometimes both - even at very low levels. They include chemicals like methyl isocyanate, chlorine, benzene, vinyl chloride, phosgene and hundreds of others. The toxic" name also distinguishes these substances from six more common air pollutants that Congress specifically ordered EPA to attack because they are found widely throughout the country - ozone,carbon monoxide, airborne particulates, sulfur dioxide, nitrogen dioxide and lead.

One indicator of the magnitude of toxic releases in this area is the Texas Air Control Board's recent estimate that industries in the five industrial counties around Houston annually release 666 million pounds of chemicals in the broad group of volatile organic compounds." These VOCs" number in the thousands and include many of the substances commonly called toxic" and many suspected cancer-causers.

I can't conceive of a place with a lot of VOC emissions that doesn't have a lot of the VOCs that cause cancer," said Bern Steigerwald, an EPA air official.

Industry has been required to reduce emissions of volatile organic compounds, as a group, because some of them help form ozone, which is one of the six priority pollutants and an ingredient of smog.

But research about most of these organic chemicals is too limited for scientists to add them either to the relatively short list of those that may cause cancer or to the longer list of those without that ability. A National Academy of Sciences committee said in 1984 noresearch had been done on the long-term risks of 70 percent of the 60,000 to 70,000 chemicals Americans are exposed to. Another 14 percent had been studied somewhat, but not enough to estimate risks.

Last year, the House Health and Environment Subcommittee said it was making the broadest effort ever to find out about releases of individual toxic chemicals. The panel asked 86 large chemical companies what amounts they release, if any, of specified substances and others with similar hazards. Twenty-nine companies in the five Houston-area counties responded to the inquiry. An analysis of the responses shows plants in those counties released - or had permits to release - about 10 million pounds of 45 of these chemicals in 1984. More than 2.5 million pounds were chemicals known or suspected to cause cancer. Almost 6 million pounds were chemicals that EPA says can kill or injure if a large enough amount escapes into the air in an accident.

The Texas Air Control Board says about 350 companies (and a few government agencies) with 491 facilities in those counties have permits to release volatile organic compounds.

Toxic releases here were compared with those in other areas in an EPA study in 1984. The study summarized what was known about sources and amounts of 86 potentially toxic air pollutants. They were mainly estimated from production figures, because EPA's data base about the actual volumes released is poor.

Virtually all of about half of these 86 substances enter the air from organic chemical plants, the study said, and the most striking aspect of their location was the large concentration between Corpus Christi and New Orleans. Eighteen of the chemicals were made entirely in Texas and Louisiana, with more than half the production of another 47 in the two states.

It appears that the Texas-Louisiana and the Philadelphia-New Jersey areas, where chemical plants are also concentrated, have the nation's largest totals of industrial releases of toxic chemicals to the air, Steigerwald said.

In the past six years, the 12,000 reports to Texas officials that described unintended releases - actual and potential - involved immediately dangerous toxic chemicals, others that may pose long-term risks, some fitting both categories, and other kinds of pollutants, aswell.

State officials say the reports as a group are as noteworthy for what they omit as for what they tell. In many cases, companies left out the identity of pollutants released, the amount, or both. Texas and Houston-area environmental officials also believe some accidental releases are never reported, but say a catastrophic release is a remote possibility.

Jim Myers, TACB's enforcement chief, said federal work place safety regulations and an aggressive effort by companies make the chance of a disastrous release a smaller concern for Texans than the possible long-term harm of routine releases.

Jon Fisher, research director for the Texas Chemical Council, said safety efforts are evident in the industry's low injury rate. The injury record of Texas chemical plants is five times better than the chemical industry's in the U.S., he said, and 10 times better than that of all American manufacturers.

Industry generally adopts safety procedures voluntarily, said Lewis Crampton, executive director of the National Institute for Chemical Studies in Charleston, W. Va. The chemical industry is highly regulated except in one area, actual production. Products are regulated, but the production process itself is not overly regulated. There are no real standards for process safety."

Some Texas and Houston-area officials gave a lukewarm reception last fall to EPA's new plan to help them prepare for disastrous toxic releases, saying they were probably already doing most of what it recommends.

Thomas said the program will increase awareness about highly toxic chemicals and preparedness for accidents. It is not a criticism of state and local officials, he said, but showed that we, EPA, didn't feel we were adequately responding to the potential threat and we did have a responsibility in that area.

It also reflected that the primary responsibility for responding to any kind of emergency as well as developing the plans was a state and local responsibility, but we had a significant role in providing technical information and technical support."

Along with advice for preparedness, EPA provided profiles of 402 chemicals that can kill or injure in an air release.

Bill Gulledge, associate environmental director of the Chemical Manufacturers Association, said EPA's effort will complement CMA's similar Community Awareness and Emergency Response program, developed and introduced after the Bhopal accident.

Critics of EPA's acute hazards plan, however, say it should formally require efforts to prevent catastrophic releases.

David Doniger, senior attorney for the Natural Resources Defense Council, said the list of 402 chemicals is useful, but should also include substances posing only long-term risks. EPA's reliance on state and local governments is worrisome, he said, because they often hesitate to seem too pushy" with major corporations, so their area will not get a reputation of having a bad business climate."

Thomas said EPA's plan for immediately dangerous releases will produce a lot of public awareness, a lot of public pressure, a lot of regulatory pressure on the plant manager" to avoid accidents, which will prompt a continuing review production of processes and reduce routine releases, too.

Doniger said procedure changes are essential, but so is abandonment of the 19th century plumbing the chemical industry now uses."

There is no bright line," dividing steps to prevent accidental and routine releases, he said. The first thing you have to do is adopt an ethic or approach that the objective is to stop using the airas a hazardous waste dump and to make these processes totally closed."

Gulledge, of the Chemical Manufacturers Association, said, however, that although the industry strives to reduce releases, zeroemissions are just not possible." Chemical plants, he said, have toemit things to the air" in some circumstances.

`Cost has something to do with it, " he said. You could cut down, but spend an absolute fortune on it." The technology is not available to stop all routine releases, he said. And chemical processes are designed for emissions at permitted safe levels."

Just how those safe levels" are determined is at the heart of the complex debate over EPA's plan to improve control of routine releases.

The Clean Air Act amendments of 1970 specified five priority pollutants for reduction around the country, and Congress added a sixth - lead - to that list in 1978.

Congress also told the new EPA 16 years ago to regulate other air pollutants - called hazardous" in the act, but also known as toxic" - that increase death or injury. To date, EPA has set regulations for six - mercury, beryllium, asbestos, vinyl chloride, benzene and radionuclides - but environmentalists say all major sources are not covered and the controls that were required were not as good as some companies already used.

EPA officials concede the program has moved too slowly. Thomas, who became EPA chief last February, said he thinks that resulted partly from the emphasis on the six priority pollutants and also from the complex technical process EPA uses to develop standards for control equipment that will be required.

Doniger and other critics in the environmental movement and Congress say EPA overcomplicated that process - and weakened its protection against cancer and other ailments - when it started asking if pollution controls were technically feasible and comparing their costs with the monetary value of the lives they would save.

EPA at first issued regulations to reduce releases of specific toxic air pollutants basically because a substance was dangerous, but an intense counterattack by industry prompted the agency to start the detailed process of deciding just how dangerous each one is and how many people are threatened. This was done to fend off lawsuits, the U.S. General Accounting Office said in 1983.

Myers said EPA has gone along at a snail's pace" because industry has fought tooth and claw to roadblock that program."

Gulledge, spokesman for the chemical industry, said it obviously will participate in the regulatory process and comment."

Whatever the reasons, Thomas said he is now speeding up and enlarging the program. That strategy is based largely on a controversial EPA study that looked at 40 chemicals and arrived at therough estimate that they cause 1,300 to 1,700 cancer cases yearly in outdoor air in the United States.

Small sources of pollutants, such as the fumes from pumps at gasoline stations, cause most of those cancers, because they are more widespread than big industrial sources, such as chemical plants and refineries, the study said.

Some people downplay the significance of health risks from industrial releases, citing that finding and another EPA study that said most people are exposed to higher levels of toxic chemicals in indoor air than outside, even living near chemical plants.

Jim Price, research director of the Texas Air Control Board, said advocates of tighter industrial controls are often haggling" and quibbling," because the EPA study said more pollutants come from small sources.

But Steigerwald, an author of the study, said large chemical plants pose much greater hazards for people nearby. I'd personally be more concerned about being in an area of high individual risk," than about living near one of the small sources, he said.

Some critics say EPA is using the study to back away from industrial controls, but Gulledge said the finding of higher risks around chemical plants suggests otherwise.

Thomas said EPA will give more attention to regulating small sources than in the past, but not at the expense of industrial controls. It is allocating more funds to set four times as many regulations per year than were imposed on industrial pollutants in thepast, he said.

Speeding up the program also involves referring" some chemicals to the states that EPA determines come from only a few industrial sources and do not warrant the expense and effort to set a federal regulation, he said.

To help the states set regulations, he said, EPA will provide increased funding and its own extensive technical resources to help determine risks and what controls are needed.

Despite such promise, the state referral program" has proven highly controversial. Critics fear that states lack the resources to handle the complex task and may impose lax regulations, if any, to keep from driving industry away.

Texas regulations now involve three tiers of controls. Reasonably available" technology is required for all sources of volatile organic compounds. Best available" technology - a step up in control - must be in place on new and modified air pollution sources. Even tighter controls are required for specific toxic chemicals with federal regulations.

State officials doubt they have the resources to set regulations for individual chemicals. We would be imprudent to say we could do it all," said Eli Bell, who becomes executive director of the Air Control Board in March.

I think we feel strongly about the control of toxics. We will look for every way we can to shift resources into that area, but there's a lot of other work we have to do in response to the (1985) amendments to the Texas Clean Air Act. Given the list I've seen (of chemicals likely to be referred to Texas), we'd be hard pressed to getit all done."

Other TACB officials were more blunt. Myers said EPA seems to be saying their record looks awful" and they're going to try to get money to give us to let us do it. They're kind of passing the hot potato down."

Next: Jobs vs. safety: A West Virginia community comes face to face with the divisive specter of toxic air pollution.