The Coalite works, which specialises in the manufacture of chlorophenols, is now in its fourth decade of controversy. The latest stage of the saga began in 1991 when high levels of dioxins were found in milk, cattle and grass on three farms near the works by the Ministry of Agriculture, Fisheries and Food (MAFF) (ENDS Report 198, p 6).
Subsequent investigations by HMIP revealed that Coalite's incinerator was emitting elevated levels of dioxins. The plant was closed down "voluntarily" (ENDS Report 203, pp 4-5). Meanwhile, the National Rivers Authority (NRA) had discovered that dioxins were also being discharged from the incinerator's scrubber, causing extensive contamination of river sediments (ENDS Report 209, p 8 ).
In the course of its investigations HMIP found that the waste feedstock for the incinerator had a total dioxin and furan concentration of 2.46mg/kg.
Earlier this year, Greenpeace secretly entered the works to take its own samples of the waste. The samples were analysed by a German laboratory, ITU-Forschung. They showed that total dioxin and furan levels were almost nine times higher than those found by HMIP, at 21.45mg/kg. Concentrations in distillation residues before they were mixed with other wastes were still higher at 87.32mg/kg.
A spokesman for Coalite commented that the wide variation between the HMIP and Greenpeace figures was "not inconsistent" with the company's own expectations.
Greenpeace says that the dioxin levels in Coalite's wastes are "extraordinarily high". It has urged HMIP to reverse its decision to give the company an integrated pollution control (IPC) authorisation for its incinerator, claiming that it will never be able to destroy the substances.
The authorisation was issued in April after Coalite had submitted an outline design proposing several improvements to its existing incinerator. These include improved burners, a possible extension of the burner chamber, computerised controls and interlocks for all key systems, the injection of powdered activated carbon into the flue gases to capture residual dioxins, and a ceramic filter to capture the carbon and other particulates. A limit of 1ng/m3 on total dioxin and furan releases has been set by the authorisation, with the "aim" being to reduce these to 0.1ng/m3.
Coalite has now moved into the detailed design phase and hopes to have the modified incinerator in operation next spring. The improvements will cost about o1.4 million.
Some doubts have been expressed about whether Coalite Chemicals' parent company, Anglo United, which has been trying to sell the business since the end of 1991, will sanction the expenditure. But a Coalite spokesman said "we have never yet been refused investment which has been aimed at environmental improvement." The incinerator, he added, "is a vital part of our business. We can't afford not to do it."
One important question posed by Greenpeace's waste sampling exercise is whether the authorisation provides adequate safeguards against dioxin releases in view of the apparent wide variability in the dioxin content of Coalite's wastes. The authorisation requires analysis of dioxin releases to air once every three months. Only one in 60 of the daily samples which are to be taken of the waste feedstock and treated liquid discharges from the plant are to be analysed for dioxins. And no dioxin sampling frequency is laid down for solid wastes from the incinerator or its emission abatement system.
Greenpeace has also taken HMIP to task for authorising the incinerator before tackling dioxin production at the works at source. An IPC application for the chlorophenol process is not due until the end of October.
Meanwhile, little progress has apparently been made in two legal actions against Coalite. According to the company, lawyers are still negotiating about a compensation claim lodged by the National Farmers' Union on behalf of three farmers whose activities were restricted by MAFF after their farms were found to be contaminated with dioxins (ENDS Report 215, p 9 ).
Almost a year ago, the National Rivers Authority announced that it would also make a civil claim to force Coalite to pay for removing dioxin-contaminated sediments from the rivers Doe Lea and Rother. The cost was tentatively estimated at about o1 million (ENDS Report 213, pp 5-6 ). But the company says it has heard nothing since from the NRA.
A third legal action may be in the offing. In a recent letter to Greenpeace requesting the results of a wide-ranging dioxin sampling exercise in the Bolsover area, HMIP said that they will be released "as soon as possible after a decision has been taken on whether to prosecute Coalite."
Any prosecution would presumably be taken under air pollution legislation which predates the Environmental Protection Act 1990, and requires operators to use the "best practicable means" to abate emissions. It is understood that HMIP has been taking statements from Coalite staff in recent months.