Restructuring £m	Restructuring environmental £m	Environmental £m	Total £m
At 1 January 2017	6.7	6.6	7.2	20.5
Increase in provision	0.2	–	2.5	2.7
Release of provision	(0.5)	–	–	(0.5)
Utilisation of provision	(2.3)	(1.4)	(0.6)	(4.3)
Exchange difference	(0.1)	(0.3)	(0.6)	(1.0)
At 31 December 2017	4.0	4.9	8.5	17.4
Included in current liabilities				8.7
Included in non-current liabilities				8.7
				17.4

The restructuring provision materially relates to the costs associated with the closure of a number of Heat Treatment sites announced in 2015 and the restructuring of the Canadian operations announced in 2016.

The Group provides for the costs of environmental remediation that have been identified, either as part of acquisition due diligence, or in other circumstances where remediation by the Group is required. This provision is reviewed annually and is separated into restructuring environmental and environmental to identify separately environmental provisions relating to the restructuring programme from those arising in the ordinary course of business.

The majority of cash outflows in respect of these liabilities are expected to occur within five years.

Whilst the Group's use of chlorinated solvents and other hazardous chemicals continues to reduce, the Group remains exposed to contingent liabilities in respect of environmental remediation liabilities. In particular, the Group could be subjected to regulatory or legislative requirements to remediate sites in the future. However, it is not possible at this time to determine whether and to what extent any liabilities exist, other than for those recognised above. Therefore no provision is recognised in relation to these items.