Up to a point, Americans should be disturbed by federal charges that mine owners in nearly half of the country's 2,000 coal mines had tampered with some coal dust samples designed to measure the risk of black lung disease. But it would be a mistake for the public to conclude that these charges amount to an indictment of the entire sampling program or justify condemning all mine operations.

The 20-month investigation by the Labor Department's Mine Safety and Health Administration claims that 4,700 instances of tampering took place in 850 mines. That includes 59 citations reported in 16 Utah coal mines. Most mine owners, who face a $1,000 fine for each tampering incident, deny any wrongdoing and plan to challenge the findings.The federally mandated samples are taken by using a pump to collect dust in a sealed filter about the size of a silver dollar. The amount of dust in the filter determines if a mine operator is complying with government standards.

Investigators said that some mine operators had vacuumed or blown dust out of filters before submitting them for analysis. Others reportedly put the cartridges outdoors to get lower dust readings.

Mine owners argue that abnormal readings in samples might be explained by causes other than tampering. They also note that the alleged infractions amount to less than 3 percent of yearly samples taken by the industry.

However, deliberate tampering is not unknown. Peabody Coal Co., the nation's largest coal producer, pleaded guilty earlier this year to charges of tampering and was hit with a $500,000 fine.

The federal government has set standards for allowable dust levels in coal mines to protect miners against black lung disease. The sickness is a disabling, sometimes fatal, respiratory ailment caused by prolonged inhalation of coal dust.

An incentive to cheat arises from the power that the federal mine agency has to close a mine if it finds too much dust in the air. Other government agencies do not have the power to close down facilities for safety violations.

Black lung once was the scourge of coal miners. Toughened safety standards have reduced the problem. But because the disease can take years to manifest itself, there are still court cases wrestling with questions of eligibility for benefits for miners or their surviving families.

It is impossible to eliminate coal dust entirely in coal mines. But air samples should be frequent, conducted in every part of a mine and, above all, be completely reliable and trustworthy.