In addition to the construction and operation of the industrial facilities, the steel plant had other dramatic effects on the landscape and environment around Muggah Creek. Between 1901 and 1990, 60 percent of Muggah Creek and a portion of Sydney Harbour were infilled to create approximately 70 hectares of land. The majority of infilling took place prior to 1950, with blast furnace slag used as the primary fill material.

In the current demolition program, a decommissioning program is designed for each structure in order to ensure that all utilities, machinery, hazardous materials and environmental concerns have been appropriately addressed prior to the removal of each structure. No studies have been undertaken to determine the presence, magnitude or extent of environmental impacts in soil or groundwater on the property.

In 2000 and 2001, Phase II and III environmental site assessments were carried out at the Coke Ovens site located immediately west of the site and the Muggah Creek estuary, or Tar Ponds, located immediately to the east. These studies were the first comprehensive sampling programs undertaken at the sites. Issues associated with these sites are well known, such as the production and disposal of coal tar and other by-products of coking operations.

Previous environmental testing at the steel plant site has tended to be concerned with specific locations or issues, such as sampling hazardous building materials or the 1994 South Substation fire. A comprehensive environmental testing program that addresses all potential environmental contamination on the steel plant site has not yet been conducted. For the most part, environmental areas of concern have been identified in this report based on past industrial activities, as obvious visible signs of impact do not tend to be widespread.

Based on past industrial activities, a brief summary of the common types of chemical contamination that may be present on the Former Sydney Steel Plant Lands follows:

Petroleum Hydrocarbons This group of organic compounds makes up many products that are in wide use in all aspects of society, including gasoline, lubricants, bunker 'C' fuel, diesel fuel, home heating oil, greases, benzene, toluene, ethyl benzene and xylenes. Depending on the location and concentration of petroleum impacts, environmental or health risks may result.

NSDEL has established contaminant guidelines and a site assessment process for the management of petroleum-contaminated sites. Depending on their molecular weight, these compounds tend to be in liquid form and associate with soil particles when released into the environment. They are usually insoluble in water, and the groundwater table often tends to act as a barrier to downward migration.

Heavy Metals - Standard laboratory analysis for this group of elements includes potential contaminants such as cadmium, mercury and lead, as well as more innocuous substances like calcium, manganese and iron. Having been a metal production and processing facility for nearly a century, surface soils on the Sydney Steel Plant property will likely contain various metals in one form or another.

Blast furnace slag, widely used as a fill material on the site, was a product of the smelting process by which iron was made. Various metals are known to be present in blast furnace slag, but in a highly immobile state that poses a low environmental risk. Recent testing has shown that "the use of slag as aggregate materials does not pose unacceptable health risks to the public in a residential setting (CRA, 2001)".

An important part of any subsequent environmental testing carried out at this site will be the appropriate evaluation of heavy metal impacts in relations to their environmental risk.

Solvents-Solvents include a variety of organic compounds such as benzene (also a petroleum hydrocarbon), perchloroethylene ("Perc"), and methylethylketone ("MEK"). These liquid chemicals are primarily used for cleaning industrial equipment. Various products have been used at the Sydney Steel Plant over the decades, and the potential exists for soil and groundwater impacts as a result of historical spills or leaks. These compounds tend to be quite mobile in the environment, although evaporation is a significant mechanism for removal from soil and surface water. Depending on the chemical composition, some solvents may be highly soluble in water, while others are practically insoluble.

PCBs -Polychlorinated biphenyls (PCBs) are a group of over 200 man-made organic compounds with a similar chemical structure. Mainly used as an electrical insulating liquid, PCBs tend to associate with soil or sediment particles in the environment, and are very slow to break down naturally. PCBs have been used in electrical transformers and similar equipment on the Sydney Steel Plant site for many years. PCBs are a regulated substance that have been linked to genetic mutation in wildlife, as well as other health effects.

PAHs - Polycyclic aromatic hydrocarbons (PAHs) are a large group of naturally occurring organic compounds formed principally through incomplete combustion such as open fires. In the same way, PAHs are formed through human activities such as bituminous coke production and campfires. Certain PAHs have been linked to cancer and other health effects.

PAHs may be present on the site as a result of atmospheric deposition from industrial activities, and high temperature processes such as open hearth furnaces. PAHs are also associated with coal tar, a substance that was produced in abundance at the adjacent coke ovens site, and release in large quantities into the environment - coal tar is the "Tar" in the Sydney Tar Ponds. Various areas of the Sydney Steel Plant property are known or suspected to be impacted by groundwater contaminated with coal tar.

HNCs - Hetrocyclic nitrogen compounds (HNCs) are another group of organic compounds associated with coal tar. As mentioned above, various areas of the Sydney Steel Plant property are known or suspected to be impacted by groundwater contaminated with coal tar. While little detailed information is known about the environmental and health effects associated with HNCs, certain compounds have long been associated with adverse health effects.

Glycols - Used extensively as a deicing agent in the airline industry, this group of compounds tend to be highly soluble in water. The latter characteristic makes glycols unfriendly to steams and other water bodies, as the rapid biodegradation can use up much of the oxygen in the receiving water body, causing inhabitants such as fish to suffocate.