In the biggest action of its kind, the Consumer Product Safety Commission and Corning Glass Works yesterday warned more than 18 million consumers that their Corning percolators could break apart and scald them.

The action was initiated by Corning, which was fined $325,000 two years ago for not alerting the government soon enough about a similar problem with another line of percolators, the CPSC and Corning said. At that time, Corning recalled 360,500 electric percolators after several consumers complained that their appliances came apart.

Yesterday's warning urged consumers to discontinue using the 18.5 million percolators sold since 1960, but keep them on hand to receive compensation through the company's plan.

Since 1972, Corning has received 7,000 complaints about the percolators, and 1,250 people claim they were injured by them. But the company only decided recently that something was wrong, the CPSC said.

"When Corning saw something more than a fluke, they let us know," said Catherine C. Cook, director of product defect correction for the CPSC.

The percolators that could be dangerous are white glass and ceramic, usually with a floral design, and are heated directly on the range or use electrical outlets. Pyrex and automatic drip coffeemakers are excluded.

Beginning Sept. 10, more than 1,000 newspapers and a women's magazine are scheduled to run advertisements instructing consumers to fill out a coupon with the percolator's serial number and other information and return the coupon to Corning. The company will determine the consumer's eligibility for other Corning products.

If eligible, the consumer will mail the percolator top to a special address, the CPSC said. Depending on the age of the percolator, the consumer is eligible for a number of options.

For instance, consumers with percolators made before 1970 may be eligible to purchase at half price Corning products worth up to $60. Others may receive cash, a 10 percent discount per year from date of manufacture on Corning products or other goods.

The cause of the problem is the epoxy sealant used to fasten the handle and metal band to the glass-ceramic pot. The sealant can dry out and become brittle, causing the two parts to separate without warning. In some cases people in the immediate vicinity have been scalded by hot coffee, the CPSC said.

The injuries range from serious scaldings requiring hospital attention to blistered feet, Cook said.

A Corning spokesman said that the company has received a number of lawsuits by injured consumers which are now being litigated. When asked why the company waited seven years before taking action on the percolators, the spokesman said, "We didn't wait so long to do anything. We made 18.5 million (percolators) and had 7,000 complaints."

The injuries and complaints represent about 4 complaints and 0.7 injury complaints per 10,000 percolators sold, the CPSC said.

The problem was similar to that in 1976, the Corning spokesman said. "There was no pattern, no predictability and the numbers (of injuries) are low," the spokesman said. In 1976, however, Cook said there were more injuries because the percolators separated earlier in their use.

Corning stopped making the percolators in 1978 with the popularity of automatic drip coffeemakers, the Corning spokesman said. He also said he didn't know how much the recall-like action would cost the company.