A state inspector saw something he shouldn't have been able to see at Lehigh Portland Cement Co. last weekend.
During a random, unannounced visit to Lehigh Feb. 23, the inspector for the Maryland Department of the Environment saw dust coming out of the stacks and issued a"site complaint" to the plant.
Maryland law requires the smoke or dust that comes out of an industry's stacks to be in such a small amount that it can't be seen.
Plant Manager David H. Roush said the malfunction that caused the emission was repaired within several hours, and the MDE confirmed the plant has passed emission tests since then.
Roush said the dust thatcame out of the stack consisted of ground limestone, shale and sand that are raw materials of the cement the plant manufactures.
"It'sstrictly a nuisance; it's not a health hazard," Roush said of the dust. He said malfunctions in the mechanical and electrical equipment happen on an average of a little more than once a month.
However, that Saturday's malfunction was the first witnessed and acted on by a state inspector in recent years, said John Goheen, a spokesman for the MDE.
The MDE is now waiting for a written explanation from the plant, Goheen said. However, the complaint is separate from the plant's pending requests to burn waste carbon and solvents in its kilns, hesaid.
"At this point, it wouldn't have any impact (on whether thepermit is issued)," Goheen said.
Roush said the dust that came from the stack was caused by an electrical short that caused a precipitator to malfunction. An electrostatic precipitator uses electrical charges to catch particles of ground stone and sand that blow up from the kiln, while still letting air escape through the stack.
The process is designed to send those particles back into the kiln, to mix with the rest of the raw material that will become cement, Roush said.
"It's an important part of the raw material, and we must have it," Roush said of the dust captured by precipitators. "What gets my goat are these unsubstantiated claims of us turning (the precipitators) off."
Some residents active in a group fighting the company's request to burn waste materials have said the company turns off the precipitators at night to save money.
"We want that dust," Roush said. "If we let it go out in the air, it upsets the chemistry in the raw material in the kiln."
The emissions prompted several calls from residents to the state's emergency hot line for reporting pollution, radiation and other such accidents after hours, said Goheen.
But he said the inspector's visit already had been planned as one of a series of unannounced inspections of Lehigh since Feb. 13. They occur about twice a week, Goheen said.
"We never really believed we'd find anything," he said. "We do this all over the state. We're not singlingout Lehigh."
The company now burns coal as its primary fuel, withsome waste oil mixed in occasionally as a lower-cost alternative fuel, Roush said.
The MDE is expected soon to issue a decision about whether to grant the company's request to burn lumps of carbon waste used for filtering water at a Ciba-Geigy chemical plant in New Jersey. The company has also asked to burn industrial solvent waste as an alternative fuel.
Both requests are opposed by a citizen group thatformed after a public hearing on the carbon permit in January. Amongtheir complaints have been the company's emitting dust, similar to the Feb. 23 incident.
"It was just belching out dust," said Julian Stein, a Union Bridge resident who was among those calling the hot line.
Stein said the incident shows the need for a continuous emission monitor on Lehigh's stacks, even if the plant doesn't burn hazardous waste. Such a monitor would allow the state to find violations even if an inspector doesn't happen to witness it, Stein said.
Goheensaid the MDE is studying a regulation for such monitors on cement plants, utilities and incinerators.
A new cement plant being built today, he said, would need such a monitor to meet federal regulations,but there is no retroactive requirement.