Section 40.0049 - Remedial Air Emissions(1) Remedial actions that involve the emission or discharge of oil and/or hazardous material to the atmosphere shall be conducted in a manner that ensures the protection of health, safety, public welfare and the environment, in conformance with 310 CMR 40.0000, 310 CMR 7.00: Air Pollution Control, and any other applicable permits, approvals, laws or regulations.(2) Except as provided in 310 CMR 40.0049(3), point-source atmospheric emissions of oil and hazardous material from remedial systems and operations including, without limitation, packed-tower or diffused aeration air strippers, bioreactors and soil vapor extraction systems shall be treated by control devices prior to their discharge to the ambient air.(3) Notwithstanding the provisions of 310 CMR 40.0049(2), except where specifically required in writing by the Department based upon its review of proposed or ongoing response actions, treatment of point-source remedial air emissions is not required at a disposal site if the untreated emissions:(a) are from an Active Exposure Pathway Mitigation Measure or passive venting system installed to mitigate the migration of subsurface vapors into living/working spaces of a building, provided the total air emission rate of all volatile contaminants is less than 100 pounds/year; or(b) would be at or below a level of no significant risk to health, safety, public welfare, and the environment; provided however, that the person undertaking the response action submits an LSP Opinion to the Department prior to commencement of the remedial action stating that such untreated emissions will present no significant risk to health, safety, public welfare and the environment, considering: 1. the mass flux and toxicities of the oil and hazardous material being emitted;2. the types and proximity of human and ecological populations;3. background concentrations of oil and hazardous material in the ambient atmosphere;4. relevant policies issued by the Department; and5. any other relevant factors.(4) Treatment of point-source remedial air emissions may be waived by the Department at sites where timely actions are needed to prevent or abate an Imminent Hazard to health, safety, public welfare or the environment. In such cases, control devices shall be installed as needed as soon as possible.(5) Except as provided in 310 CMR 40.0049(7), air-emission control devices shall be designed, constructed, and operated in a manner that will ensure removal of at least 95% of the emitted oil and hazardous materials, on a weight basis.(6)Monitoring Requirements for Remedial Actions That Require the Use of an Off-gas Control System. To ensure compliance with the 95% VOCs reduction performance standard, each person performing response actions at a disposal site pursuant to M.G.L. c. 21E, and 310 CMR 40.0000 that require the use of off-gas control systems to reduce the emission or discharge amounts of oil and/or hazardous material to the atmosphere shall: (a) collect and analyze influent and effluent vapor samples from the off-gas control system one, seven, 14 and 28 days after system start-up, and monthly thereafter; and(b) document the results of the monitoring in the appropriate status report or Remedial Monitoring Report.(7) Notwithstanding the provisions of 310 CMR 40.0049(5), except where treatment standards are specified in writing by the Department based upon its review of proposed or ongoing response actions, a Licensed Site Professional may submit an Opinion to the Department that achievement of a 95% level of emission reduction is not feasible or necessary at a disposal site, based upon an evaluation of conventional treatment technologies and risks to surrounding human or ecological populations. This Opinion shall be accompanied by an alternative treatment control plan that will be implemented at the disposal site.(8) No provision of 310 CMR 40.0049(3) or (7) shall relieve any person conducting response actions of their obligations to comply with all applicable permitting requirements and treatment standards specified in 310 CMR 7.00: Air Pollution Control.Amended by Mass Register Issue 1503, eff. 3/1/2024.Amended by Mass Register Issue S1516, eff. 3/1/2024.