On Oct. 4, 99 pages of fine print in the Federal Register were given over to proposed new government rules for the "identification, classification and regulation of toxic substances posing a potential occupational carcinogenic risk."

Dutifully, the newspapers carried stories about a new federal policy for combating cancer-causing substances in the workplace.

Then almost everyone forgot the issue - everyone, that is, except the chemical industry.

To DuPont, Dow and other giants of chemistry, those 99 pages of dull gray print were a call to arms.

Within a matter of weeks, the chemical industry had assembled an expertly staffed, full-blown organization to do battle over the Occupational Safety and Health Administration's 99 pages.

About 40 of the largest chemical companies were contacted directly or through their network of trade associations, and most of them committed personnel and money to the cause.

Top exeutives of DuPont, Allied, Dow and other chemical giants formed an executive council, and committees were assembled to deal with everything from legal strategy to research and public relations. Up to 2,000 corporations were being solicited for help in industries ranging from brewing to steelmaking.

By the time the group was ready to public in late November, it had given itself a name worthy of a lobbying hall of fame: "The American Industrial Health Council."

The chemical industry's mobilization for regulatory war was impressive, but hardly unprecendented.

Over the years since World War II, there has been a regulatory explosion in Washington and a proliferation of lobbying efforts to influence the process, often involving a virtual who's who of American industry, labor and other interest groups.

Once regulatory activity was centered mainly on commerce. Now it has branched into nearly everthing as Congress reponded to problems and pressures by creating new regulatory agencies to deal with them. In the 1970s alone, the government embarked on new regulatory ventures ranging from air and water quality to boat safety, noise abatement, pension guarantees and protections from job hazards.

Almost any day, in government hearing rooms scattered all over Washington and often as far away as Alaska and Hawaii, dozens of corporations, unions, trade associations and other lobbying groups can be found testifying so techincal that only trade publications bother to report the details.

It is Washington's homegrown form of guerrilla welfare, usually obscured by better-publicized lobbying fights on Capitol Hill but often more important in impact.

The Occupational Safety and Health Act case in point.

When it was passed in 1970, the act set up a bureaucaracy within the Labor Department to devise and enforce rules to limit accident and health hazards that workers face on their jobs. Obvious targets were chemicals and other substances believed to cause cances.

But it wasn't until OSHA, conceding the failure of its earlier attempts to control each cancer-causer on a substance-by-substance basis, proposed a comprehensive set of procedures for limiting workers exposure to all suspected carcinogens that the chemical industry sensed an immediate threat and responded.

A look at both the Labor Department, the parent agency of OSHA, and Dow Chemical USA, one of the prime movers in the impeding fight over the cancer, policy, indicates how the regulatory net has spread and how industry copes with it.

The department started out shortly after the turn of the century as a social welfare and informational agency. "It has now turned the conner and become a regulatory agency as much as anything else," noted a departmental information officer, Donald S. Smyth.

Two years, ago former Labor Secretary John T. Dunlop prepared a memorandum on the subject that counted 134 departmental regulatory programs: a nearly 8-fold increase over the 18 regulatory programs that the department administered in 1940.

The list continues to grow. Mine safety enforcement, one a resposibility of the Interior-Department, was added just this year.

The department's regulatory responsibilities ranges from protecting workers against job discrimination to deciding longshoremen's compesation cases. Just since 1970, it has taken on occupational health and safety, black lung compensation, pension protection and mine safety.

The number of administrative law judges, who preside over regulatory hearings, is one barometer of the growth of regulatory activity.

For the government as a whole, the increase is dramatic enough: from 196 when the Administrative Procedures Act was passed in 1946 to nearly 1,100 this year, according to Charles J. Dullea of the Civil Service Commission.

But for the Labor Department it is even more staggering: from for in 1971 to 45 this year, not counting the 43 judges who serve the OSHA Review Commission, a related but independent body that passes judgment on OSHA enforcement actions.

Dow, the nation's third largest chemical company with $5.6 billion in annual sales last year, opened a Washington office during World War II and has been on the scene ever since.

It belons to various trade association lobbying groups but also has its own staff of 20, with specialists targeted on specific departments and agencies such as labor, where it monitors "just about everything that goes on," according to public relations manager Jim Hansen.

Increasingly, Dow's lobbying workload is shifting from Congress to the lureaucracy, although it fluctuates widely depending on the issues involved, Hanses said. "Any company will tell you its fastest-growing department is its legal department, and its legal department is dealing mainly in regulatory matters," he said.

Hansen is also a public relations dipector for the "American Industrial Health Council," which has already won an intial skirmish in its battle over OSHA's proposed cancer policy.

In alengthy letter to Labor Secretary Ray Marshall and OSHA Administrator Eula Gingham over the name of its Washington law firm (Cleary, Gottlieb, Steen & Hamilton), the group objected that OSHA was not allowing enough time for comment and preparations for hearing initially scheduled for March 14. Late last month OSHA, apparently sensing a law suit in the making, postponed the comment deadlines and rescheduled the hearings for April 4.

Still pending is another major complaint which could also find its way into the courts some day - that OSHA should list the substances it intends to regulate before itpropounds procedures for regulating them. OSHA officials contend that this would put the cart before the horse; the chemical companies argue that do do otherwise would eny them due process.

So the battle is, on. "Things are moving pretty fast," said Dow's Hansen. "Fortunately we don't have to opporate like the government. When you get the top people involved, it all moves pretty rapidly."