Fly-tipping, by definition, is illegal dumping of waste onto roadsides or unlicensed land. It is unsightly and potentially toxic, and hazardous to both people and wildlife. It also imposes significant financial burdens, to properly dispose of the waste and get land safely cleaned up again afterwards. Spillage of contaminated waste into watercourses and groundwater is another cause of damage that is even harder to quantify.
Remediation work is often hindered by the lack of identification of the dumped materials and contents, as potentially identifying marks are often deliberately removed.
Who is at risk?
We are all put at risk in a variety of ways. Physically, we are put at risk because farmland and watercourses may be contaminated. Eventually we eat, drink or inhale the consequences. Many modern products, like old sofas and mattresses, contain volatile organic compounds, old building materials may contain lead or asbestos, and electrical goods leech a variety of toxic metals.
Legally and financially, we are at risk too. You may believe you have paid legitimately to dispose of waste items, but if the companies paid to take it away decide to dump it somewhere they shouldn’t, that illegal dumping may still be traceable back to you.
Similarly, the owners of the land on which items are dumped are not excused from responsibility for it. In fact, it is ultimately the landowner or tenant that is likely to be forced to meet the cost of its removal and all the other remedial work that it could involve. It is for this reason that under English law, fly-tipping is a criminal and not a civil offence, and should be reported to the police as a crime, (see https://www.gov.uk/report-flytipping).
Using reputable and fully qualified waste disposal companies to clear and remediate land is not only common sense, it is a legal protection. There is often considerably more involved than dragging everything onto the back of a truck and carting it away (this is why criminals dump stuff in the first place). Removing or neutralising old storage tanks, for example, is a speciality in itself, especially when the contents are unknown or prove to be environmentally problematic. For details of tank decommissioning, see http://www.ashremediation.co.uk/tank-decommissioning/.
Your specialist will collate all the chemical and physical data needed to achieve proper regulatory sign offs for you.