Supervisors at Pepco's Potomac River power plant are sick over the company's strike preparations.

In fact, they are nauseous, feverish and wracked with abdominal pain. Some have headaches, and others just need a rest.

"It was a management mistake," a Potomac Electric and Power Co. spokesman said, explaining the mini-disaster. "It wasn't an act of union sabotage or anything."

The company inadvertently pumped in untreated Potomac River water to trailers housing 80 to 100 supervisors on strike alert at the plant in Alexandria. The supervisors had been standing by in case the company's contract dispute with Local 1900 of the International Brotherhood of Electrical Workers led to a walkout by 3,500 unionized employes.

But the microbes struck instead.

Late Wednesday night, some of the supervisors began calling the company's doctor, complaining about nausea and other intestinal difficulties. H.G. Shoemaker, director of environmental health for the City of Alexandria, also received calls from some of the supervisors, complaining that the trailers' drinking water connections were bringing in river water, normally used for cooling purposes in plant operations.

At least 16 of the supervisors became ill, although none was seriously affected, company officials said yesterday.

Pepco spokesman William H. Jones said the company discovered the water-hook-up error after receiving several reports of illness Wednesday. He said the company immediately called in the Alexandria City Health Department to begin a series of tests on the stricken supervisors.

Shoemaker said the city has taken stool samples, which are being examined for coliform bacteria, which come from sewage. The tests will take 48 to 72 hours to complete, he said.

In the interim, the company has changed the water supply connections. And gamma globulin shots, used in the prevention of several infectious diseases such as hepatitis are being administered to all of the affected supervisors.

The invading bugs could undermine the company's strike plans. Alexandria officials said the trailers could be closed if the illnesses persist.

Local 1900 officials could not be reached for comment yesterday on the latest unsettling development in their talks with the company.

And it will be too late today to try to get a comment out of them. The on-again-off-again negotiations that began Feb. 25 are on again at 1 p.m. today. But the union and the company have decided to conduct the rest of their talks under a media blackout.

The negotiations will be held at the offices of the Federal Mediation and Conciliation Service, which has been presiding over the talks for the past three weeks.

Contract talks between Pepco and the IBEW broke off Monday after federal mediators decided the two sides were too far apart on economic and related issues to continue meeting. The mediation service asked the two sides Wednesday to return to the bargaining table today.

Basic disagreements between the company and the union, which has been operating without a contract since a three-year pact expired May 31, reportedly involve wages, Pepco's proposed changes in job classifications, and proposed sick-leave changes. Pepco's unionized workers voted overwhelmingly two weeks ago to authorize a strike against the utility, a move considered a standard bargaining procedure.

Pepco serves 525,204 customers in the District of Columbia, and in Montgomery and Prince George's counties in Maryland, and in Arlington County in Virginia. Pepco's Strike Plans Cramped By Warren Brown and Nancy L. Ross Washington Post Staff Writers

Supervisors at Pepco's Potomac River power plant are sick over the company's strike preparations.

In fact, they are nauseous, feverish and wracked with abdominal pain. Some have headaches, and others just need a rest.

"It was a management mistake," a Potomac Electric and Power Co. spokesman said, explaining the mini-disaster. "It wasn't an act of union sabotage or anything."

The company inadvertently pumped in untreated Potomac River water to trailers housing 80 to 100 supervisors on strike alert at the plant in Alexandria. The supervisors had been standing by in case the company's contract dispute with Local 1900 of the International Brotherhood of Electrical Workers led to a walkout by 3,500 unionized employes.

But the microbes struck instead.

Late Wednesday night, some of the supervisors began calling the company's doctor, complaining about nausea and other intestinal difficulties. H.G. Shoemaker, director of environmental health for the City of Alexandria, also received calls from some of the supervisors, complaining that the trailers' drinking water connections were bringing in river water, normally used for cooling purposes in plant operations.

At least 16 of the supervisors became ill, although none was seriously affected, company officials said yesterday.

Pepco spokesman William H. Jones said the company discovered the water-hook-up error after receiving several reports of illness Wednesday. He said the company immediately called in the Alexandria City Health Department to begin a series of tests on the stricken supervisors.

Shoemaker said the city has taken stool samples, which are being examined for coliform bacteria, which come from sewage. The tests will take 48 to 72 hours to complete, he said.

In the interim, the company has changed the water supply connections. And gamma globulin shots, used in the prevention of several infectious diseases such as hepatitis are being administered to all of the affected supervisors.

The invading bugs could undermine the company's strike plans. Alexandria officials said the trailers could be closed if the illnesses persist.

Local 1900 officials could not be reached for comment yesterday on the latest unsettling development in their talks with the company.

And it will be too late today to try to get a comment out of them. The on-again-off-again negotiations that began Feb. 25 are on again at 1 p.m. today. But the union and the company have decided to conduct the rest of their talks under a media blackout.

The negotiations will be held at the offices of the Federal Mediation and Conciliation Service, which has been presiding over the talks for the past three weeks.

Contract talks between Pepco and the IBEW broke off Monday after federal mediators decided the two sides were too far apart on economic and related issues to continue meeting. The mediation service asked the two sides Wednesday to return to the bargaining table today.

Basic disagreements between the company and the union, which has been operating without a contract since a three-year pact expired May 31, reportedly involve wages, Pepco's proposed changes in job classifications, and proposed sick-leave changes. Pepco's unionized workers voted overwhelmingly two weeks ago to authorize a strike against the utility, a move considered a standard bargaining procedure.

Pepco serves 525,204 customers in the District of Columbia, and in Montgomery and Prince George's counties in Maryland, and in Arlington County in Virginia.