Posted: November 10, 2001
This page is categorized as:    link to Outrage Management index
Hover here for
Article SummaryA recurring question among my clients is: “Why can’t we just explain the data so people won’t be outraged any more?” This article reports some research on the efficacy of technical information as a way to shape risk perception. The results are not encouraging to my clients’ fondest hopes.
Testing the Role of Technical Information in
Public Risk Perception
RISK: Issues in Health and Safety, Fall 1992, pp. 341–364
(Page 3 of 4 – Return to page 1 link up to index)

Appendix I: Simulated Stories
Used in This Study

Three of the five simulated stories used in this study are reproduced below. They are, in sequence:

The Low-Outrage High-Detail Low-Magnitude Story

MAPLE RIDGE – A lightning strike during last night’s thunderstorm ruptured a chemical holding tank at Chemsol Inc., spilling a cancer-causing cleaning solvent called perchloroethylene onto neighboring residential lawns.

Perchloroethylene, more commonly called PERC, is a colorless liquid used as a cleaning agent or degreaser.

Chemsol, located on North Highway at Ridge Road, manufactures a range of chemical products used in dry cleaning and by the metal industries.

According to B.J. Chester, emergency response coordinator for the New Jersey Department of Environmental Protection, it was “a very unusual event” for lightning to cause a holding tank to burn and then rupture. The lightning apparently struck a valve right at the base of the tank, he said.

According to Chester, Chemsol’s tanks meet all required standards. “We will certainly want to take another look at the regulations,” Chester said. “Perhaps the agency should consider tougher standards for lightning protection.” Chester said he would recommend that DEP consider requiring dikes around the tanks to prevent chemicals from escaping if there is a rupture.

About six families live less than a mile from the Chemsol holding tanks. The nearest family is a quarter mile away.

Neighbors said only about a third of the homes in the neighborhood draw their water from wells. Assuming this is true, Chester said, “two wells at most are facing a possible PERC contamination.”

“Soon after I woke up there was a DEP person at my door explaining what happened and what the cleanup crews were doing.” – Maple Ridge resident

Chester said DEP would be developing plans to test area wells for PERC. “At this point I wouldn’t expect any wells to be seriously contaminated,” Chester said. “But we still want to test to be sure.”

Clara Stevenson, whose home is the closest one to the site of the spill, said she was “impressed” by DEP’s promise to test her well. “I’m much less upset now that I have talked to the DEP people,” she said.

Scientific research has linked long-term PERC exposure to liver cancer in mice and leukemia in rats. Although no evidence has been found concerning cancer in humans, EPA considers PERC a “suspected human carcinogen.” State standards for PERC permit no more than one part per billion in drinking water. Although not all scientists agree, it is estimated that an average adult who drank PERC contaminated water for an entire lifetime at the highest level of PERC allowed under government standards would have an increased cancer risk of up to one in a million as a result.

Chester said the spill did not pose any risk of breathing in PERC contaminated air, because the PERC in the puddles would spread quickly as soon as it reached the air, and would “almost immediately” become much too dilute to endanger anyone’s health.

He said the only way local residents might get a significant short-term PERC exposure from the spill was by drinking water from the puddles or direct skin contact with the puddles. He advised residents to keep children and pets out of the puddles until they have had a chance to evaporate.

He said the possible longer-term risk to residents with wells near the spill could not be estimated yet. “The risk to any particular well depends on the amount of PERC spilled, how close the spill is to the well, and what sort of soil separates the PERC from the well,” he explained.

DEP tested puddle water on the Chemsol site last night and plans to test again today, but the results won’t be back from the laboratory for two to three weeks, Chester said. Water samples were also taken from nearby lawns.

He said that preliminary data “which will have to be confirmed” indicated that last night’s levels in neighborhood puddles were probably above the state drinking water standard, “perhaps as high as five parts per billion,” five times the standard. He said it was not possible to estimate how much of the PERC might eventually soak down to well water, “but it would surely be much less than in the puddles.”

According to the U.S. Environmental Protection Agency’s Office of Drinking Water, short-term exposure to breathing high levels of PERC can cause a wide range of health effects.

However, Chester said these effects would result only from breathing in concentrated PERC vapors, and could not happen to Maple Ridge residents.

He said DEP had made arrangements with the county health department to check with the nearest residents later today to make sure they have no symptoms of overexposure. “Even though we are fairly confident that at the levels we think are present no symptoms are likely,” he said, “checking with people is a way to make sure and at the same time answer their questions.”

“Soon after I woke up there was a DEP person at my door explaining what happened and what the cleanup crews were doing,” said Maple Ridge resident Alex Sands

The High-Outrage Low-Detail Low-Magnitude Story

MAPLE RIDGE – A lightning strike during last night’s thunderstorm ruptured a chemical holding tank at Chemsol Inc., spilling a cancer-causing cleaning solvent called per-chloroethylene onto neighboring residential lawns.

Perchloroethylene, more commonly called PERC, is a colorless liquid used as a cleaning agent or degreaser.

Chemsol, located on North Highway at Ridge Road, manufactures a range of chemical products used in dry cleaning and by the metal industries.

According to B.J. Chester, emergency response coordinator for the New Jersey Department of Environmental Protection, it was “a very unusual event” for lightning to cause a holding tank to burn and then rupture. The lightning apparently struck a valve right at the base of the tank, he said.

According to Chester, Chemsol’s tanks meet all required standards. “It looks like a fluke to me,” Chester said. “As far as I know, DEP has no plans to reexamine the regulations. You can’t cover every conceivable event.” Chester said he would not recommend that DEP consider requiring dikes around the tanks to prevent chemicals from escaping if there is a rupture.

About six families live less than a mile from the Chemsol holding tanks. The nearest family is a quarter mile away.

Neighbors said only about a third of the homes in the neighborhood draw their water from wells. Assuming this is true, Chester said, “two wells at most are facing a possible PERC contamination.”

“I have no idea what happened or what they’re doing about it, and nobody from DEP is taking the time to tell me.” – Maple Ridge resident

Chester said DEP had no plans to test area wells for PERC. “At this point I wouldn’t really expect any wells to be seriously contaminated,” Chester said. “People who want to be sure will have to make their own arrangements.”

Clara Stevenson, whose home is the closest one to the site of the spill, said she was “furious” about DEP’s unwillingness to test her well. “My whole family is upset and the DEP people just don’t seem to care,” she said.

Scientific research has linked long-term PERC exposure to some kinds of cancer in test ani-mals. State standards for PERC permit no more than one part per billion in drinking water.

Although not all scientists agree, it is estimated that an average adult who drank PERC contaminated water for an entire lifetime at the highest level of PERC allowed under government standards would have an increased cancer risk of up to one in a million as a result.

Chester said the spill did not pose any risk of breathing in PERC contaminated air, only a possible water problem. He advised residents to keep children and pets out of the puddles until they have had a chance to evaporate. He said the possible longer-term risk to residents with wells near the spill could not be estimated yet.

DEP tested puddle water on the Chemsol site last night and plans to test again today, but the results won’t be back from the laboratory for two to three weeks, Chester said. Water samples were also taken from nearby lawns.

He said that preliminary data “which will have to be confirmed” indicated that last night’s levels in neighborhood puddles were probably above the state drinking water standard, “perhaps as high as five parts per billion,” five times the standard. He said it was not possible to estimate how much of the PERC might eventually soak down to well water, “but it would surely be much less than in the puddles.”

According to the U.S. Environmental Protection Agency’s Office of Drinking Water, short-term exposure to breathing high levels of PERC can cause a wide range of health effects.

However, Chester said these effects would result only from breathing in concentrated PERC vapors, and could not happen to Maple Ridge residents.

He said there was no need to check for symptoms in nearby residents, because “we are fairly confident that at the levels we think are present no symptoms are likely.” Asking an expert to check with people, he said, “would be a senseless use of overtaxed agency resources and might just provoke hysterical responses in people who are not really at any risk.”

“I have no idea what happened or what they’re doing about it, and nobody from DEP is taking the time to tell me,” said Maple Ridge resident Alex Sands.

The Low-Outrage High-Detail High-Magnitude Story

MAPLE RIDGE – A lightning strike during last night’s thunderstorm ruptured a chemical holding tank at Chemsol Inc., spilling a cancer-causing cleaning solvent called perchloroethylene onto neighboring residential lawns.

Perchloroethylene, more commonly called PERC, is a colorless liquid used as a cleaning agent or degreaser.

Chemsol, located on North Highway at Ridge Road, manufactures a range of chemical products used in dry cleaning and by the metal industries.

According to B.J. Chester, emergency response coordinator for the New Jersey Department of Environmental Protection, it was “a very unusual event” for lightning to cause a holding tank to burn and then rupture. The lightning apparently struck a valve right at the base of the tank, he said.

According to Chester, Chemsol’s tanks meet all required standards. “We will certainly want to take another look at the regulations,” Chester said. “Perhaps the agency should consider tougher standards for lightning protection.” Chester said he would recommend that DEP consider requiring dikes around the tanks to prevent chemicals from escaping if there is a rupture.

About 200 families live less than a mile from the Chemsol holding tanks. The nearest family is only 100 yards away.

Neighbors said virtually all the homes near the spill draw their water from wells. Assuming this is true, Chester said, “all 200 wells face a possible PERC contamination.”

“Soon after I woke up there was a DEP person at my door explaining what happened and what the cleanup crews were doing.” – Maple Ridge resident

Chester said DEP would be developing plans to test area wells for PERC. “At this point I wouldn’t really expect any wells to be seriously contaminated,” Chester said. “But we still want to test to be sure.”

Clara Stevenson, whose home is the closest one to the site of the spill, said she was “impressed” by DEP’s promise to test her well. “I’m much less upset now that I have talked to the DEP people,” she said.

Scientific research has linked long-term PERC exposure to liver cancer in mice and leukemia in rats. Although no evidence has been found concerning cancer in humans, EPA considers PERC a “suspected human carcinogen.” State standards for PERC permit no more than one part per billion in drinking water.

Although not all scientists agree, it is estimated that an average adult who drank PERC contaminated water for an entire lifetime at the highest level of PERC allowed under government standards would have an increased cancer risk of up to one in 10,000 as a result.

Chester said the spill did not pose any risk of breathing in PERC contaminated air, because the PERC in the puddles would spread quickly as soon as it reached the air, and would “almost immediately” become much too dilute to endanger anyone’s health.

He said the only way local residents might get a significant short-term PERC exposure from the spill was by drinking water from the puddles or direct skin contact with the puddles. He advised residents to keep children and pets out of the puddles until they have had a chance to evaporate.

He said the possible longer-term risk to residents with wells near the spill could not be estimated yet. “The risk to any particular well depends on the amount of PERC spilled, how close the spill is to the well, and what sort of soil separates the PERC from the well,” he explained.

DEP tested puddle water on the Chemsol site last night and plans to test again today, but the results won’t be back from the laboratory for two to three weeks, Chester said. Water samples were also taken from nearby lawns.

He said that preliminary data “which will have to be confirmed” indicated that last night’s levels in neighborhood puddles were probably above the state drinking water standard, “perhaps as high as 100 parts per billion,” a hundred times the standard. He said it was not possible to estimate how much of the PERC might eventually soak down to well water, “but it would surely be much less than in the puddles.”

According to the U.S. Environmental Protection Agency’s Office of Drinking Water, short-term exposure to breathing high levels of PERC can cause a wide range of health effects.

However, Chester said these effects would result only from breathing in concentrated PERC vapors, and could not happen to Maple Ridge residents.

He said DEP had made arrangements with the county health department to check with the nearest residents later today to make sure they have no symptoms of overexposure. “Even though we are fairly confident that at the levels we think are present no symptoms are likely,” he said, “checking with people is a way to make sure and at the same time answer their questions.”

“Soon after I woke up there was a DEP person at my door explaining what happened and what the cleanup crews were doing,” said Maple Ridge resident Alex Sands.

Copyright © 2001 by Branden B. Johnson, Peter M. Sandman, and Paul Miller

For more on outrage management:    link to Outrage Management index
      Comment or Ask      Read the comments
Contact information page:    Peter M. Sandman

Website design and management provided by SnowTao Editing Services.