1. SUBPART N MACT AMENDMENTS QUESTIONS & ANSWERS 40 CFR PART 63, SUBPART N

2. Q/A 1. Does a facility have to comply with the OSHA standard? OSHA had considered non- regulatory approaches, but feels that rulemaking is a necessary step to ensure that workers are protected from the hazards of hexavalent chromium. The U.S. Court of Appeals has ordered OSHA to move forward with a final rule. OSHA had considered non- regulatory approaches, but feels that rulemaking is a necessary step to ensure that workers are protected from the hazards of hexavalent chromium. The U.S. Court of Appeals has ordered OSHA to move forward with a final rule.

3. Q/A 2. Are fume suppressants the only means of emissions control on hard chrome electroplating tanks? USEPA has evaluated the results of several emissions tests that demonstrate the performance of wetting agent fume suppressants in controlling chromium emissions from Subpart N effected sources. USEPA concluded that surface tension is the primary factor in determining chromium emissions from electroplating baths. USEPA has evaluated the results of several emissions tests that demonstrate the performance of wetting agent fume suppressants in controlling chromium emissions from Subpart N effected sources. USEPA concluded that surface tension is the primary factor in determining chromium emissions from electroplating baths.

4. Q/A 3. Would the Subpart N Amendment allow existing add-on emissions controls to be removed from Subpart N effected sources? USEPA recognizes that under the Subpart N final amendment, owners/operators of hard chrome electroplating tanks that choose to comply with the surface tension limit could remove existing add-on emission controls. In light of the pending OSHA hexavalent chrome work place PEL reduction, both approaches may be valid. USEPA recognizes that under the Subpart N final amendment, owners/operators of hard chrome electroplating tanks that choose to comply with the surface tension limit could remove existing add-on emission controls. In light of the pending OSHA hexavalent chrome work place PEL reduction, both approaches may be valid.

5. Q/A 4. Are the wetting agent fume suppressants equivalent to the add-on control capability of controlling chromium emissions from Subpart N facilities? USEPA has reviewed the available data on the performance of wetting agent fume suppressants and concluded the wetting agent fume suppressants demonstrate that control of chromium emissions achieved by add-on controls is equivalent to the level achieved by maintaining the electroplating bath surface tension below the limits specified in Subpart N. USEPA has reviewed the available data on the performance of wetting agent fume suppressants and concluded the wetting agent fume suppressants demonstrate that control of chromium emissions achieved by add-on controls is equivalent to the level achieved by maintaining the electroplating bath surface tension below the limits specified in Subpart N.

6. Q/A 5. Should an effected source be required to complete a performance test as required for the use of add-on controls in Subpart N? USEPA has concluded that Subpart N facilities would not be required to conduct performance tests under the Subpart N amended requirements if the owner/operators of effected sources decided to comply with the surface tension limits instead of the current add-on emissions limits. An emissions test is not required. USEPA has concluded that Subpart N facilities would not be required to conduct performance tests under the Subpart N amended requirements if the owner/operators of effected sources decided to comply with the surface tension limits instead of the current add-on emissions limits. An emissions test is not required.

7. Q/A 6. Is the mass emissions limit determined by calculations under §63.344 a reasonable alternative to the emissions concentration limit for enclosed hard chrome electroplating tanks? USEPA concludes that the emissions rate limit is a reasonable alternative to the emissions concentration limit in the original promulgated rule. Furthermore, USEPA concluded that enclosing hoods increase capture efficiency and provide an added benefit by reducing worker exposure to electroplating tank emissions. USEPA concludes that the emissions rate limit is a reasonable alternative to the emissions concentration limit in the original promulgated rule. Furthermore, USEPA concluded that enclosing hoods increase capture efficiency and provide an added benefit by reducing worker exposure to electroplating tank emissions.

8. Q/A 7. Why did USEPA increase the operating limit for the pressure drop across a CMP system from +/-1 in. w.c. to +/-2 in. w.c.? USEPA became aware that the pressure drop operating limit across a CMP often exceeds the pressure drop operating limit by more than +/-1 in. w.c. immediately following the replacement or cleaning of pads. Consequently, USEPA has increased the allowable range of pressure drops from +/-1 in. w.c. to +/-2 in. w.c. USEPA became aware that the pressure drop operating limit across a CMP often exceeds the pressure drop operating limit by more than +/-1 in. w.c. immediately following the replacement or cleaning of pads. Consequently, USEPA has increased the allowable range of pressure drops from +/-1 in. w.c. to +/-2 in. w.c.

9. Q/A 8. How can an owner/operator establish a new CPM operating limit? The owner/operator can establish a new operating limit for CPM pressure drop by repeating the performance test. The pressure drop across the CMP system does not apply during automatic washdown cycles of the CMP system. The owner/operator can establish a new operating limit for CPM pressure drop by repeating the performance test. The pressure drop across the CMP system does not apply during automatic washdown cycles of the CMP system.

10. Q/A 9. What must a facility do to guarantee compliance with Subpart N if the facility made any changes due to the OSHA PEL requirement? If approved, the facility must complete performance tests and codify the alternate in the operating permit. If approved, the facility must complete performance tests and codify the alternate in the operating permit.

11. Q/A 10. If a Subpart N source is located at a Major source for HAPs, does the Subpart N source require a Title V permit? An effected facility located at a Major source must be included in the Title V permit for the facility. An effected facility located at a Major source must be included in the Title V permit for the facility.

12. Q/A 11. Does a Subpart N facility have to comply with the emission limitations during periods of startup, shutdown and malfunction? The effected facility must be in compliance with the emissions limitations, work practice standards, and operation and maintenance requirements in Subpart N at all times, EXCEPT during periods of startup, shutdown and malfunction, (i.e., during washdown cycles, startup from washdown maintenance, etc.). The effected facility must be in compliance with the emissions limitations, work practice standards, and operation and maintenance requirements in Subpart N at all times, EXCEPT during periods of startup, shutdown and malfunction, (i.e., during washdown cycles, startup from washdown maintenance, etc.).

13. Q/A 12. Are the requirements for reporting under Part 70, Title V fully covered in Subpart N? USEPA considered whether Title V would add any significant compliance requirements to those already required by NESHAP. After a comparison of the compliance requirements of the NESHAP to those of Title V, USEPA concludes that they are substantially equivalent. Historically, the NESHAP are designed to stand alone with regard to compliance requirements and reporting compliance on a timely basis. USEPA has therefore decided that taking all of the factors together, Title V permitting would be unnecessarily burdensome on area sources USEPA considered whether Title V would add any significant compliance requirements to those already required by NESHAP. After a comparison of the compliance requirements of the NESHAP to those of Title V, USEPA concludes that they are substantially equivalent. Historically, the NESHAP are designed to stand alone with regard to compliance requirements and reporting compliance on a timely basis. USEPA has therefore decided that taking all of the factors together, Title V permitting would be unnecessarily burdensome on area sources