Gasworks nightmare revisited?

SEVERAL weeks after the main clean-up operation on a heavily-polluted former gasworks site at Heworth was completed, an oily reek still hangs in the air.

After a couple of minutes it catches you at the back of the throat, leaving a bitter taste.

Mark Perrin is used to it; but even the regional director of consultants Encia, who were brought in by Persimmon to clean up the land, admits it is there. It is like creosote, he says. "A bit coal-tarry."

The reason the smell hasn't all gone is that the clean-up hasn't actually finished. Yes, 80,000 tonnes of heavily-contaminated surface soil has been removed. But now, polluted groundwater needs to be dealt with.

Encia workmen are punching boreholes deep into the ground to suck up oily chemicals which leaked into aquifers far beneath the surface. Once the worst of the pollutant has been removed, agents will be injected through the boreholes to treat the water and ensure any remaining pollutant is cleaned up.

The process of decontaminating the groundwater is expected to be completed by next autumn. Fortunately for nearby residents, the odours it produces are far less strong than those caused by clearing away the soil itself.

So bad was the smell at times over the summer, when the clean-up was in full swing, that one family fled their homs in the middle of the night to escape the fumes, and ended up sleeping in a lay-by.

Alastair Robinson, who lives with his wife Caroline and their two young daughters in Dalguise Grove just opposite the gasworks site, says for months they were living in fear about the possible harmful effects of the vapours.

He claims they suffered sore throats, respiratory infections and other problems. And no one, he insists, would give them any cast-iron assurances that the fumes were not harmful.

Now Alastair and other residents fear the whole nightmare could be about to start all over again. Secondsite Property Holdings have applied for planning permission to build more than 300 homes and 1,800 square metres of offices on another piece of former gasworks land right next door to the Persimmon site. And before any building work can begin there, that site, too, will have to be cleaned up.

So how worried about the possible effect on their health should residents be?

Mark Perrin's company has no contract to clean up the second site, so he can't comment in detail on that. But he insists that at no point were residents at risk during the clean-up of the Persimmon site.

The contaminants found there included arsenic and cyanide. These, however, were comparatively unimportant. They don't move

xxxxxxx

anywhere and are no risk to anyone while buried in the ground, Mark says.

The real problem was the oily petrochemicals that, through decades of the site being used as a gasworks, had been produced as a by-product of burning coal to produce gas, and which had seeped into the ground.

The surface soil up to a depth of between three and five metres was impregnated with this stuff, Mark says; and it was this that gave off the noxious odour as the soil was cleared and trucked away to be dumped in special contaminated waste sites.

Simply leaving the stuff there wasn't an option, he insists: eventually the poison could have seeped from the soil into the River Foss; or, as had begun to happen, into even deeper groundwater aquifers far beneath the surface.

But it was while this heavily-contaminated surface soil was being lifted and removed that the noxious vapours were released - leaving nearby residents at the mercy of the wind. Residents' concerns centred upon fears that these vapours could be harmful to their health - and even potentially cancer-causing.

Is that so? A report commissioned nearly 20 years ago into contaminants at the site does say that certain chemicals such as coal tars or "other toluene extractable materials" can have a carcinogenic effect - if they come into contact with the skin.

There is all the difference in the world, however, between actually coming into contact with these chemicals in concentrated form and the kind of bad smells released during the clean-up, Mark says.

Health and Safety Executive guidelines on exposure to such vapours stipulate that at no time should the airborne concentration exceed one part per million at the boundary of the site being cleaned.

Encia staff monitored the air quality at various points around the site three times a day - and not once did the concentrations even approach that level, Mark says. Usually they were no more than 0.2 or 0.3 parts per million.

On the site itself they did exceed that - which was why workmen sometimes had to use protective gear. But the vapour was very quickly diluted by fresh air, and those higher concentrations did not extend away from the site itself.

So, hand on heart, would he have wanted to live just across the road in Dalguise Grove during the clean-up if he had had a young family?

He pauses for a moment. "In terms of not wanting to be exposed to odour nuisance, no," he says. "But in terms of my family being at risk, it would not be a problem."

So what about the second gasworks site? It does, after all, have a giant gas cylinder planted right in the middle of it. Is it likely to be more heavily polluted, and therefore more of a risk during any clean-up?

Actually, no, Mark believes. The gas-producing facility was on the site his company is cleaning now. The gas cylinder on the site next door was a much later addition, and would have been used only to store, not to make, gas. If anything, he believes the second site will be much less contaminated than the first.

The city council agrees. Residents like Alastair Robinson, however, are still worried. Parts of the site may be less contaminated, he says: but parts of it are likely still to be heavily polluted. "And if it takes one month to clean up instead of five months, that is still one month of hell," he says.

Alastair accepts the need to clean up the pollution. "Nobody is complaining about the end result," he says. "What we're upset about is the process." In particular, he is furious about what he claims was the lack of prior warning about the fumes last time, and the general lack of information.

He also believes the clean-up could have been managed better, so as to minimise the release of odours.

To some extent, Coun Andrew Waller, City of York Council's executive member for environment and sustainability, agrees. The council has learned lessons, he says.

He is satisfied that there was no health risk from the clean-up of the first site. "But the smells were still unpleasant," he admits.

The council will hope to use the experience of that first clean-up to try and ensure a better job is made second time around. So can he give a guarantee that there will be no health risk to nearby residents?

Any clean-up plan will have to be approved by the council, he says. "We do our best to ensure that health and safety is not put at risk, and we have powers to stop the developers doing anything that is dangerous."

None of which wholly convinces residents. A worried Alastair actually presented planners last month with a list of "residents' requirements" detailing the way they would like to see a clean-up conducted if planning approval is given for the second site.

The list included a request that the council insist on an independent overseer to monitor the clean-up, and that restrictions be placed on the way contaminated soil is exposed and removed.

But if he is not satisfied with the council's response, he says, he and his family will seriously consider moving out for the duration of any clean-up - and asking the council to provide alternative accommodation. "We are very fed up," he says.

Why the site is polluted

The York Gas Light Company was founded in 1822 and built a gas manufacturing plant on the west bank of the Foss (where Sainsbury's car park is now) in 1824. In the 1880s, a second plant was built on the East bank of the Foss - the site that is now being cleaned up.

Gas was produced at the plants by heating coal in a retort in the absence of air. Still impure, the gas was then passed through condensers and scrubbers to remove tar, and then through iron oxide purifiers to remove other impurities.

It is the oily by-products of gas production that over decades seeped into the ground, causing pollution.

Why it must be cleaned up

Two main reasons. Firstly, to leave the pollution there risks contamination of groundwater deep under the surface.

Secondly, there is great pressure on local authorities to reclaim brownfield land for development, instead of building on greenfield land.

"Brownfield sites can be problematic," admits Coun Andrew Waller, City of York Council's executive member for the environment. "But we cannot just leave land in the city centre idle and build on all the green belt."

Updated: 10:58 Friday, December 10, 2004