The Petrolia Discovery Foundation is reporting another act of vandalism at its historic site, leaving a large price tag.
Significant damage was reported at the property during the overnight hours of March 26, which is set to cost an estimated $20,000.
The foundation said the majority of the windows, many over 100 years old, were broken and there is potential interior damage.
Vandalism has been reported at the property over the last several months.
In November, four suspects gained access to the building and caused an estimated $500 in damage.
Board Chair Liz Welsh said the destruction and associated cost of this incident are beyond what the organization has seen.
"This is far too much work for volunteers," said Welsh. "Our organization is dedicated to preserving Petrolia Discovery for future generations, but repeated acts of vandalism make this mission incredibly challenging."
Lambton OPP have been notified and launched an investigation.
The foundation said it remains committed to reopening for the summer by July.
Anyone with information is asked to contact police at 1-888-310-1122 or Crime Stoppers at 1-800-222-8477.