Actors' Equity Association and the League of American Theatres and Producers have set absolute limits on the amount of smoke that can be used safely on stages. The move was spurred by a report commissioned by the two groups, which concluded that actors are at risk when exposed to "elevated or peak levels of glycol smoke and mineral oil."

However, it also noted that if exposure levels are kept below the limits established in the study, actors should "not suffer adverse impacts to their health or their vocal abilities." The study, which took three years to complete, was jointly prepared by the Mt. Sinai School of Medicine and the ENVIRON International Corporation. It included the participation of 439 actors performing in 16 Broadway musicals during the 1997-1998 seasons. In four of those productions, Jekyll & Hyde, Les Miserables, Miss Saigon and Phantom of the Opera, the potential peak concentration of smoke exceeded the recommended levels. Of those shows, only Les Miserables and Phantom are still running.

According to Ken Greenwood, Equity's senior business representative, "Those productions will now have to assess whether actors are subjected to peak exposure levels and whether the exposures can be reduced through changes in the blocking or choreography. If such changes cannot be made, an adjustment in the amount of smoke discharged will be necessary. We will also review exposure levels in any new production to make sure they are in compliance with the guidelines."

The study recommends the following guidance levels with respect to glycols and mineral oil: The use of glycols should be such that an Actors' exposure does not exceed 40 milligrams per cubic meter (mg/m3); mineral oil should be used in such a manner that an Actors' exposure does not exceed a peak concentration of 25 mg/m3; for chronic exposures to mineral oil, the existing standards established for oil mists (5 mg/m3 as an eight-hour time-weighted average) should also be protective for actors in theatrical productions.

The full report can now be seen on the Equity website. The documents include an executive summary (8 pages), equipment-based guidelines (50 pages), guidance presentation (18 pages), and study presentation (17 pages).

Manufacturers of smoke and fog products, are for the most part, in favor of the ruling. “It’s very good,” Le Maitre’s Adrian Segeren told Entertainment Design. “It’s finally going to level the playing field. In the past there are a few companies who have had a leg up on things, and now this balances out a little more. So I’m pretty pleased.”

In a press release, Stan Miller, president of Rosco, says, “We are please to see that the study performed by the Mt. Sinai School of Medicine completely vindicates both Rosco’s studies and those of the National Institute of Occupational Safety and Health. The first conclusion in the Equity report is “no evidence of serious health effects was found to be associated with exposure to any of the theatrical effects evaluated in this study.’

“We felt all along that Rosco had a special responsibility with regard to theatrical smoke since we have been the prime supplier since we introduced these fluids in 1979," he continues. "This study…clearly established that theatrical smoke and haze, when properly used, remains a useful and viable stage technique, on Broadway and everywhere else.”

Karl Ruling, technical standards manager for ESTA, says the ruling benefits both the industry and the actors. “They are low enough that performers can be assured that they will not have any ill effects from performing in fog,” he explains. “The levels are also high enough that good fog effects are possible. Therefore, this is a good thing all around. The performers are protected and assured, the designers get the effects they want, and the audience gets a good show.”