The process by which airborne fiber levels are measured is, unfortunately, enormously time-consuming. It requires the use of a complex air pumping device which, attached to a worker's belt, draws air through a hose connected to a filter pinned to his lapel. But even if measurement is taken over a two or three-hour period, it may not reflect the full extent of contamination, since the most dense exposure may occur only once a day or less when the substance is poured from shipping sacks into mixing bins, for example, generating huge plumes of dust.

Even after these ambient fiber levels have been determined, control is prohibitively expensive. Workers must be supplied with respirators, and working areas must be enclosed to prevent the spread of contamination. Powerful ventilation must be constructed. Similar precautions must be taken wherever asbestos products are sanded, drilled, ground, pressed or even handled extensively.

Dusty conditions often ensue in the packing of powdery asbestos admixtures, such as cement. Good housekeeping procedures become essential: floors must be periodically vacuumed, and the dust collectors of ventilation systems emptied on a regular basis. Working clothes must be changed immediately before returning home to eliminate uncontrolled exposure. The ventilation systems required to cleanse and recirculate the plant atmospheres are often so elaborate that ceilings must be kept clean; two or three inches of asbestos dust may collect on them in a very short time. An operation so simple as shoveling old brake shoes into a disposal vehicle may present a considerable danger.

Each plant must design and institute an abatement and surveillance program tailored to fit its specific contamination problems. The choice for these plants is either to protect their workers or close down.

While industrial exposures are being slowly mitigated, it remains to be seen whether or not any steps will be taken to reduce the sort of community exposure that, in its extreme form, began to occur twenty years ago in Johannesburg. Asbestos exposures at Harvard, for example, are no less severe than in other urban communities. A substantial occupational danger exists where University-employed workers sand down old vinyl and asbestos floor tiles to make a flat surface on which to lay new ones. Pipe insulation installers become covered with crumbling asbestos sealants while working in the steam tunnels that connect Harvard buildings. The incessant swirl of stop-and-go traffic around Cambridge exposes us all to fibers ground off brake shoe linings. Demolition and construction activities on the Nathan M. Pusey Library and Canaday Hall constitute another major source of asbestos pollution.

Chances are that those of us developing mesothelioma will not be afflicted by it for another 30 or 40 years. Perhaps an increasing cancer or sarcoma mortality rate is one of the "occupational hazards" of being an urban dweller. Our generation will have to take such things in stride. But what about those ahead of us who will be exposed not only to that asbestos produced in their own lifetimes but also to all of the residue produced in our own? Perhaps in a university like ours, endowed with such a wealth of creative talent and scientific resources, it may still be possible to free ourselves from the malignancies of the magic mineral.