De Minimis for Air Emissions
Any activity or workplace that causes contaminants to be released into the air in Texas requires authorization from the TCEQ. De minimis is one of four choices a small business owner or local government representative may have available to them to satisfy air authorization requirements in Texas. The other three are:
If a small business owner or local government representative determines that an operation or activity meets the requirements of the De Minimis Rule and can show suitable proof that de minimis applies to their location, then no other state air authorization is required.
Ways to be De Minimis
List of De Minimis Facilities
Reviewing the List of De Minimus Facilities or Sources is the easiest way to determine if an operation qualifies for a de minimus authorization. That list may be obtained at:
The list may also be obtained by calling the TCEQ's Air Permits Division in Austin at 512-239-1250 and asking for the latest list of De Minimis Facilities.
De Minimis Rule
Material Use - Paragraph 2 of the rule shows de minimis limits by the amount and type of materials that are allowed to be used in a year's time. View the rule at 30 Texas Administrative Code, Chapter 116
Effects Screening Levels (ESL) - Paragraph 3 of the rule shows how a facility meets the De Minimis Rule by evaluating the daily and annual emissions from the site. This chart shows the sitewide emission rate caps based on ESL: 30 TAC Chapter 116.119(a)(3) (PDF), (Help with PDF)
Record Keeping: It's the Law
Although record keeping is important for any operation, it is especially important for a small business or local government claiming de minimis. The overall requirements for keeping appropriate records and the authorization for TCEQ investigators to examine those records are found in the Texas Health and Safety Code, Subtitle C, Air Quality, Chapter 382: Monitoring Requirements and Examination of Records (Section 382.016)
At a minimum, de minimis record keeping should consist of invoices for amounts of materials purchased. Facility owners and operators should maintain enough information to demonstrate they meet the De Minimis Rule requirements. Remember that these records must be produced upon request.
The phrase "de minimis" literally means "of minimum impact." It is intended that qualification for de minimis means there will be no significant contamination of the air. And it is also important to remember that the entire job site must meet de minimis standards in order to qualify under this rule.
Don't forget that de minimis is just one option when it comes to satisfying state air authorization requirements in Texas. Facilities that do not qualify for de minimis may pursue a more appropriate authorization such as Permit by Rule, Standard Permit, or a New Source Review Permit. For free and confidential assistance in seeking air authorizations or compliance guidance regarding air, water, waste, or pollution prevention issues, please contact the Small Business and Local Government Assistance Section at 1-800-447-2827 or a Compliance Assistance Specialist in your area.