Certain processes in the manufacture of our current and past products create by-products classified as hazardous waste. We have been notified by the U.S. Environmental Protection Agency, state environmental agencies, and in some cases, groups of potentially responsible parties, that we may be potentially liable for environmental contamination at several sites currently and formerly owned or operated by us. Two of those sites, Asheville, North Carolina and Mountain View, California, are designated National Priorities List sites under the U.S. Environmental Protection Agency’s Superfund program. We accrue a liability for probable remediation activities, claims and proceedings against us with respect to environmental matters if the amount can be reasonably estimated, and provide disclosures including the nature of a loss whenever it is probable or reasonably possible that a potentially material loss may have occurred but cannot be estimated. We record contingent loss accruals on an undiscounted basis.

A roll-forward of remediation reserves included in accrued expenses and other liabilities in the Consolidated Balance Sheets is comprised of the following:

	Years Ended December 31,
	2021			2020			2019
Balance at beginning of period	$	10,642		$	11,444		$	11,274
Remediation expense		2,254			2,769			2,602
Remediation payments		(1,929	)		(3,639	)		(2,455	)
Other activity ⁽¹⁾		12			68			23
Balance at end of the period	$	10,979		$	10,642		$	11,444

Unrelated to the environmental claims described above, certain other legal claims are pending against us with respect to matters arising out of the ordinary conduct of our business.

We provide product warranties when we sell our products and accrue for estimated liabilities at the time of sale. Warranty estimates are forecasts based on the best available information and historical claims experience. We accrue for specific warranty claims if we believe that the facts of a specific claim make it probable that a liability in excess of our historical experience has been incurred and provide disclosures for specific claims whenever it is reasonably possible that a material loss may be incurred which cannot be estimated.

We cannot provide assurance that the ultimate disposition of environmental, legal, and product warranty claims will not materially exceed the amount of our accrued losses and adversely impact our consolidated financial position, results of operations, or cash flows. Our accrued liabilities and disclosures will be adjusted accordingly if additional information becomes available in the future.