A key seat on the Consumer Product Safety Commission still remains open, and no White House action is expected soon.

The new member is expected to tip the balance of the current commission, however. Terrence M. Scanlon, the new CPSC chairman, appears to have an ally in Commissioner Carol G. Dawson. Dawson has maintained a low profile since she was appointed last year, abstaining on many votes. But commission sources say her votes so far suggest that her views are closer to Scanlon's than to other members'.

Saundra Brown Armstrong, a Reagan appointee, is seen as a middle-of-the-road commissioner whose votes can swing in either direction. Sometimes they swing toward the side of Commissioner Stuart M. Statler, the only holdover from the Carter administration and the member who most strongly supports regulation.

The two people most frequently mentioned for the open seat are Camille Haney and Anne Graham. Haney, a Wisconsin Republican, is president of Haney Co., a Milwaukee-based consulting firm that specializes in consumer affairs.

Sen. Robert W. Kasten Jr. (R-Wis.), who chairs the Senate Commerce subcommittee that oversees the five-member CPSC, had urged President Reagan to nominate Haney as commission chairman, and reportedly was angry when Scanlon got the job as a recess appointee.

Although Haney initially said she was interested only in the CPSC chairmanship, sources say she has changed her mind.

However, another CPSC source said that Graham, now assistant secretary of Education for legislation and public affairs, "practically has the nomination all locked up." The same source said the White House wants to appoint a woman to the seat.

Neither Haney or Graham could be reached for comment.

No action is expected soon, in part because of the recent shake-up in the White House Personnel office. John S. Herrington, who headed the office, has been nominated to be secretary of Energy. White House nominations have been delayed by the impending departures of James A. Baker III, Michael K. Deaver and Edwin Meese III, who used to sign off on all presidential appointments.

"I wouldn't expect any action until there's some settling of the waters at the White House Personnel Office, and Donald T. Regan is firmly entrenched" as chief of staff, a CPSC source said. OLDER CONSUMERS . . .

Next month, the CPSC will begin a nationwide campaign to focus attention on the safety of elderly persons. "The CPSC decided there was a need to increase the awareness of the vulnerability of the elderly," said Armstrong, who is heading the project.

The agency plans to distribute a checklist identifying the most common accidents that senior citizens experience at home. "The elderly are frequently victims of falls around the house," Armstrong said. Home accidents include slipping on mats and rugs and falling on stairs, in bathtubs and when reaching up to cabinets.

Armstrong said the agency will be recommending that slip-resistant tape be attached to mats and rugs, that light switches be installed at the top and bottom of stairs and that handrails be installed on both sides of stairways. The agency will also encourage elderly persons to use step-stools with handles and to install grab-bars in their bathrooms.

Armstrong said the program, which is to be launched Feb. 21 at the U.S. Capitol, will include training sessions for older consumers and visits to the homes of elderly persons.

The CPSC has set aside $25,000 for its five regional offices to spend on the campaign. They'll be trying to encourage state and local governments and private groups to provide most of the help. Philadelphia's city government has committed itself to inspecting homes and helping elderly persons correct hazardous situations.