Cal Check, LLC
11600 Black Horse Run, Raleigh, NC 27613
p: 919.847.1898    f: 919.847.8005    e:
smoke stack testing


• The US EPA has unleashed the new Performance Specification 1 (40 CFR 60, Appendix B), effective April 9, 2001. For a copy of the rule, link to the federal register at:

• For method 9 training and equipment as well as some history of opacity dating from way back, visit

Onsite Training

We offer both half day and full day training for opacity audits and data review, as well as trouble shooting.

John Rosenquest's Credentials

John Rosequest is the owner and operator of Cal Check. With over 25 years in business, Cal Check is the nation’s leading independant opacity CEM filter certification lab. Cal Check serves facilities from all 50 states and several foreign countries annually. John develops new test equipment and test filters for opacity monitors, with vendors.

In addition, John has trained source operators and state agency personnel to perform opacity audits. He has worked with groups facilitating the development of new opacity regulations with consultants, opacity vendors and regulators. John graduated from Virginia Tech with a Masters in Environmental Science and Engineering.

Contact John Rosenquest at .