Whose fault? Company or customer

''Dear Clorox, we love your bleach. In fact we use it all the time - to brush our teeth.'' Of the roughly 3,000 consumer calls and letters Clorox receives a month, it gets some 10 to 20 off-the-wall letters. And it illustrates the kind of problem all manufacturers have with product safety: It is very difficult to know if their product, be it bleach or a blender, is unsafe or is just being improperly used.

Companies, usually the market leaders, have come a long way in sorting out such product safety dilemmas. They've drawn closer to their customers by beefing up their customer service departments and providing the toll-free 800 numbers. But falling in the cracks of good business practice are those companies that fear bad publicity or simply choose to lay the blame for misuse in the customer's lap. In the last two years there is evidence that suggests some companies have interpreted Reagan deregulation efforts as a signal to relax safety standards.

''Unfortunately, many companies view it (product safety problems) as customer incompetence. Most businesses haven't adopted the approach that if customers screw up, it's our problem, too,'' says John A. Goodman, president of Technical Assistance Research Programs Inc. (TARP), a customer service research and consulting firm in Washington, D.C.

Mr. Goodman, who has assessed customer service and complaint handling systems in over 200 corporations and government agencies, believes misuse or incompetence is a factor that companies must address. ''Approximately 50 percent of the product problems consumers experience are more or less of their own making.'' (Incidentally, as Goodman tells the toothbrushing story, the letter also asked, ''Couldn't you do something to make Clorox taste better?'')

So, educating the consumer to use the product properly is one safety-improvement path. But getting the consumer to take that trail doesn't always work, according to Mr. Goodman. ''Often, they simply don't read the directions or don't follow them. I know of one computer company that has resorted to putting on it's box in big red letters: 'When all else fails try reading the directions.' ''

More companies are using the ''800'' numbers to provide a channel for teaching both consumer and company about product use or misuse. In 1978 there were some 40,000 toll-free 800 numbers, says Mr. Goodman. Now there are 10 times that many - with about 100,000 being used for servicing customers.

The 800 numbers ensure quick response. This may mean saving the loss of not only dissatisfied customers, but potential new ones. One study TARP did recently for the Coca-Cola Company revealed that every dissatisfied customer told nine or 10 people. Whereas every satisfied customer told five people, some of whom may become new customers. In addition to heading off bad grapevine publicity, a fast response can short-circuit legal problems.

''The propensity to get into lawsuits is directly proportional to response time,'' says Goodman. ''If you can respond by telephone, you can find out what the customer did to contribute to the problem. Written complaints may go through several departments before ending up in the legal department. If a person is given three weeks to stew, he will have gotten advice from all his neighbors and filter out anything he may have done to contribute to the problem.''

Moreover, the longer a company takes to respond, the more likely the consumer will complain to a consumer group or government organization, perhaps generating unnecessary bad publicity. If a real product safety problem arises, many companies are required by law to report it to the government, which may in turn ban the product or require changes to make it safer.

Some businesses have chafed at this snitch-on-yourself law, and in the last year such reports to the Consumer Product Safety Commission were ''way down.''

''I see no indication that reporting is off, because products are safer,'' says Mark Silbergeld, director of the Consumers Union Washington, D.C., office. In 1982 the CPSC received only 96 possible substantial safety hazard reports from manufacturers, compared with 121 in 1981 and 201 reports in 1979.

''A substantial part of the business community feels, 'Hey, we've identified the problem and we'll fix it quietly','' says Mr. Goodman. They're very much afraid that if it gets in the government mill, it's a target for publicity. There's a lot of cynicism that the CPSC does things for publicity purposes. I think Nancy Steorts (head of the commission) is playing it fairly straight. But, the CPSC doesn't have the staff to find things on their own. It's very possible that some companies are taking advantage of that.''

The Reagan administration's cuts in the CPSC in 1981 (see sidebar) has sent a signal to business that it doesn't have to worry about product safety laws, say consumer advocates.

Jeffrey Perlman, director of government relations at the Chamber of Commerce of the United States, disagrees with this reading. ''It's foolish to suggest that business won't report product safety problems because of one agency or another's weakness. I don't think a business is going to look at Washington's attitudes and simply ignore the law.''

''In every function of business over the last two years, I'm not aware of any cutback in product safety,'' concurs Murray L. Weidenbaum, director of the Center for the Study of American Business at Washington University in St. Louis. ''In fact, quality control functions have been accentuated. The GM factory in Missouri recently postponed production because they had a safety question about the transmission. Of course, in this case the watchdog agency is not the CPSCbut the National Highway Traffic Safety Administration.''

Mr. Goodman also notes that great strides have been made in corporate concern for product safety. But, ''it's generally the leading firms that are concerned about quality and image that play it straight while the second-tier companies, that may be not as aggressive, like to keep their heads down. They think that if they notify the CPSC, they're just asking for it,'' Goodman says.

Those companies, he argues, could take a lesson from Johnson & Johnson and how it handled the Tylenol tampering scare. ''J&J was very forthright. And, if anything, they ended up with a very positive image. May be even more positive after (the incident) than before. Sales are recovering very well and so is their image.''

The reason J&J weathered the storm so well, says Goodman, is that they had ''built a foundation of confidence ahead of time. It was assumed they were not guilty. And when the problem was discovered, J&J aggressively communicated their situation. They cleared the shelves immediately and sent out 600,000 mailgrams to doctors, pharmacists, etc., in the first week.''

Companies that don't take the time or money to build customer confidence, says Goodman, ''are assumed guilty until proven innocent.''