The Consumer Product Safety Commission is expected to announce today that it is taking the first step in developing a mandatory standard to make cigarette lighters child resistant, commission sources said yesterday.

The commission, which has voted unanimously to begin collecting information from the public about injuries and from lighter manufacturers about voluntary standards, had come under increasing pressure from both Congress and consumer groups for failing to ensure the safety of disposable lighters. The commission's proposal would include all lighters, not just disposable lighters.

Cigarette lighter safety came to wide attention last year after it was revealed that dozens of suits have been filed against Bic Corp., the maker of the most popular brand of disposable lighter. Congressional hearings on the issue were held last summer.

About 200 people die each year from fires caused by lighters, according to the CPSC statistics. About 140 of those are children.

"Cigarette lighters available today are not child resistant," the commission said in a draft of the statement to be released today. "To provide child resistance, changes in lighter design may be required."

"It's an important first step in addressing a hidden hazard that kills hundreds of people each year," said Mary Ellen Fise, a lobbyist for the Consumer Federation of America. "While parents would not let their kids play with bleach or acid, they don't see the same type of hazard with lighters."

However, Fise expressed concern that commission staff members have estimated that final rulemaking could take until 1992. The initial comment period should last about a year, one commission source said.

Rep. James J. Florio (D-N.J.), chairman of the House commerce, consumer protection and competitiveness subcommittee, has been critical of the commission's lethargy in pursuing lighter safety. Florio said yesterday that while he was pleased with this action, "careful public scrutiny of the commission will be required to ensure that the process now moves forward as expeditiously as possible."

Florio has introduced legislation to restructure the CPSC that will be considered by the commerce committee when Congress reconvenes.

Proponents of a mandatory standard said that some standards -- such as warning labels -- would not be sufficient to address what they consider the real problem of the lighters' design.

The commission's action was based on a proposal by Diane Denton, a nurse in Louisville, Ky., who petitioned the CPSC in 1985 to make disposable lighters child-resistant. Denton reported that over a two-year period about one-half of the children treated in Kosair Children's Hospital's burn unit after lighter accidents were younger than 4.

A study by the commmission in 1986 and 1987 showed that 96 percent of the lighters involved in fires were disposable butane lighters.

The CPSC decision is the latest of a number of problems the cigarette lighter industry is facing. Last year, Bic said that more than 40 lawsuits had been filed against the company alleging that its lighters exploded, causing severe injury or death.

Officials of Bic Corp. could not be reached for comment late yesterday. However, they have said in the past that they are working to design a lighter that is childproof. Until that time, the company is putting warning labels on its lighters.