"It really looked like a battlefield," wrote one witness to the June 5 incident.
Eventually, 11 union members went to jail for the attack.
It was the flash point in a 16-year battle between Altemose, who became a national symbol for the "open-shop" construction industry, and the mighty Philadelphia trade unions. Those unions generally had ignored the small, nonunion projects in the suburbs - that is, until Altemose refused to guarantee the unions all of the work on his $16.5 million hotel/office complex.
Twenty years later, major construction projects in Philadelphia, such as the convention center, remain union. In the suburbs, too, large jobs - for instance, the developments by three pharmaceutical companies on the Route 422 corridor, and the Tower Bridge buildings in Conshohocken and West Conshohocken - tend to be union.
Altemose's Valley Forge Convention Center has declared bankruptcy. So has he.
So does that mean the union war on Altemose succeeded? Hardly.
"It certainly didn't stop the growth of open-shop construction," said John J. Reith, director of labor relations for the General Building Contractors Association, which represents union contractors and subcontractors.
"Altemose became a symbol, a rallying point, for open-shop contractors across the country," said Peter Cockshaw, a Newtown Square labor analyst who publishes Cockshaw's Construction Labor News & Opinion.
In fact, everyone agrees: Open-shop or nonunion construction has taken an increasingly larger portion of the construction dollar. Herbert R. Northrup, a former professor at the Wharton School who has studied the industry, estimates that nationwide, nonunion labor gets 75 percent of the construction dollar.
But Philadelphia, he says, "remains pretty much a union town."
A 1988 survey by the contractors association shows union contractors getting 96 percent of the dollar volume in Philadelphia jobs - and 76 percent in the five-county area. In number of projects, though, 70 percent went to nonunion contractors.
The association has stopped assembling data, because too many job sites today have a mix of union and nonunion workers. Union contractors even find themselves having to hire nonunion subcontractors to meet a tight budget - something unheard of years ago.
"A general contractor, to be competitive, may feel it's not economically possible to hire a union subcontractor," said Walter P. Palmer Jr., the contractors association's executive director. "It's just that it's a highly competitive market."
Two weeks after the incident at the Valley Forge Sheraton, about 20,000 construction workers, some in hard hats and crewcuts, others in ponytails and beards, marched from Plymouth Meeting to the Montgomery County Courthouse in Norristown to protest nonunion projects.
Then on Aug. 18, hours after arrest warrants were issued in the Valley Forge attack, Altemose was beaten in Center City by men and women picketing a bank that financed his projects. Altemose walked away with a black eye - and reams of publicity as the builder who dared to defy the unions. Three roofers were charged with beating him, but were acquitted.
That incident, along with the Valley Forge attack, gained the Altemose/ union battle national notoriety - including a segment on 60 Minutes.
The Altemose affair was "kind of a watershed, and was very traumatic" for the unions, said Mark Forrest, spokesman for the Philadelphia AFL-CIO. "In a sense, it was nose-rubbing. It was very, very high-profile . . . and, in a sense, Altemose seemed to be saying, 'We're going to take on organized labor, and we're going to win.' "
In the eyes of nonunion builders, the attack "focused attention on the problem of union violence," said M. Kirk Pickerel, executive director of the Southeastern Pennsylvania chapter of Associated Builders & Contractors Inc., a group of open-shop contractors. With the attacks on Altemose and his site, union members came off as "a bunch of goons," Cockshaw said.
But Patrick B. Gillespie, business manager of the Building and Construction Trades Council of Philadelphia and Vicinity, says the incidents revealed less about union behavior than about Altemose's mastery of public relations.
"He became the darling of every Chamber of Commerce. He became the nonunion darling," Gillespie said. "We got into an arena of public relations, and all we had on our side was being right."
Gillespie minimizes the damage at the Valley Forge site. As it turned out, he says, the damaged equipment was owned by a union contractor, and unions paid to repair or replace it. He says the incident resulted from "an overzealousness that went awry."
"There wasn't a criminal intent. What was done there was done out of outrage and out of an attempt to protect a living standard that subsequently has been eroded," Gillespie said.
Today, Altemose is quiet on the whole subject. An aide says that, under a settlement with the Building Trades Council, he cannot discuss it. Altemose sued the council for federal antitrust violations. In 1988, the two sides settled for more than $1 million, according to an Altemose spokeswoman, but less than $1.5 million, according to the unions.
So who won? Perhaps that chapter has not been written.
"In the final analysis, I'm not sure we lost, because Altemose (is) out of business and we're still in business," said Forrest of the AFL-CIO. He doesn't condone the violence, but says labor had to show its disapproval or it would have tacitly accepted Altemose's role in eroding wages and living standards.
"None of these tactics by the union will work in the end," said Daniel J. Bennet, executive vice president of the Associated Builders & Contractors, which is based in Washington. Since 1972, his group has grown from 4,952 members to 17,000.
"Strikes, pickets, violence, boycotts, corporate campaigns, financial
pressure - none of it will work," Bennet said. "This country is driven by economics, and they've just got to get competitive."
The unions say they're doing just that. Under pressure from nonunion builders, they've come up with something called Built-Rite, a program that brings unions, contractors and owners in cooperation on construction. Its executive director, Jim Martin, winces when he hears references to Altemose.
"Nobody harkens back to that as the good old days," he said. "There's a modern way of doing business, and it's through improved communication and concern for the quality of a product."