I think you want 40 CFR 262.34.=A0 You can see the whole reg. at www.epa.gov

Martin Quinn

=A7262.34 Accumulation time.

(a) Except as provided in paragraphs (d), 262.34(e), and (f) of this section, a generator may accumulate hazardous waste on-site for 90 days or less without a permit or without having interim status, provided that:

(a)(1) The waste is placed:

(a)(1)(i) In containers and the generator complies with the applicable requirements of subparts I, AA, BB, and CC of 40 CFR part 265; and/or

(a)(1)(ii) In tanks and the generator complies with the applicable requirements of subparts J, AA, BB, and CC of 40 CFR part 265 except =A7=A7265.197(c) and 265.200; and/or

(a)(1)(iii) On drip pads and the generator complies with subpart W of 40 CFR part 265 and maintains the following records at the facility:

(a)(1)(iii)(A) A description of procedures that will be followed to ensure that all wastes are removed from the drip pad and associated collection system at least once every 90 days; and

(a)(1)(iii)(B) Documentation of each waste removal, including the quantity of waste removed from the drip pad and the sump or collection system and the date and time of removal; and/or

(a)(1)(iv) In containment buildings and the generator complies with subpart DD of 40 CFR part 265, has placed its professional engineer certification that the building complies with the design standards specified in 40 CFR 265.1101 in the facility's operating record no later than 60 days after the date of initial operation of the unit. After February 18, 1993, PE certification will be required prior to operation of the unit. The owner or operator shall maintain the following records at the facility:

(a)(1)(iv)(A) A written description of procedures to ensure that each waste volume remains in the unit for no more than 90 days, a written description of the waste generation and management practices for the facility showing that they are consistent with respecting the 90 day limit, and documentation that the procedures are complied with; or

(a)(1)(iv)(B) Documentation that the unit is emptied at least once every 90 days.

In addition, such a generator is exempt from all the requirements in subparts G and H of 40 CFR part 265, except for =A7=A7265.111 and 265.114.

(a)(2) The date upon which each period of accumulation begins is clearly marked and visible for inspection on each container;

(a)(3) While being accumulated on-site, each container and tank is labeled or marked clearly with the words, "Hazardous Waste"; and

(a)(4) The generator complies with the requirements for owners or operators in subparts C and D in 40 CFR part 265, with =A7265.16, and with all applicable requirements under 40 CFR part 268.

(b) A generator of 1,000 kilograms or greater of hazardous waste in a calendar month, or greater than 1 kg of acute hazardous waste listed in =A7=A7261.31 or 261.33(e) in a calendar month, who accumulates hazardous waste or acute hazardous waste for more than 90 days is an operator of a storage facility and is subject to the requirements of 40 CFR parts 264, 265, and 267 and the permit requirements of 40 CFR part 270 unless he has been granted an extension to the 90-day period. Such extension may be granted by EPA if hazardous wastes must remain on-site for longer than 90 days due to unforeseen, temporary, and uncontrollable circumstances. An extension of up to 30 days may be granted at the discretion of the Regional Administrator on a case-by-case basis.

(c)(1) A generator may accumulate as much as 55 gallons of hazardous waste or one quart of acutely hazardous waste listed in =A7261.31 or 261.33(e) in containers at or near any point of generation where wastes initially accumulate which is under the control of the operator of the process generating the waste, without a permit or interim status and without complying with paragraph (a) or (d) of this section provided he:

(c)(1)(i) Complies with =A7=A7265.171, 265.172, and 265.173(a) of this chapter; and

(c)(1)(ii) Marks his containers either with the words "Hazardous Waste" or with other words that identify the contents of the containers.

(c)(2) A generator who accumulates either hazardous waste or acutely hazardous waste listed in =A7=A7261.31 or 261.33(e) in excess of the amounts listed in paragraph (c)(1) of this section at or near any point of generation must, with respect to that amount of excess waste, comply within three days with paragraph (a) of this section or other applicable provisions of this chapter. During the three day period the generator must continue to comply with paragraphs (c)(1)(i) and (ii) of this section. The generator must mark the container holding the excess accumulation of hazardous waste with the date the excess amount began accumulating.

(d) A generator who generates greater than 100 kilograms but less than 1000 kilograms of hazardous waste in a calendar month may accumulate hazardous waste on-site for 180 days or less without a permit or without having interim status provided that:

(d)(1) The quantity of waste accumulated on-site never exceeds 6000 kilograms;

(d)(2) The generator complies with the requirements of subpart I of part 265 of this chapter, except for =A7=A7265.176 and 265.178;

(d)(3) The generator complies with the requirements of =A7265.201 in Subpart J of Part 265;

(d)(4) The generator complies with the requirements of paragraphs (a)(2) and (a)(3) of this section, the requirements of subpart C of part 265, with all applicable requirements under 40 CFR part 268; and

(d)(5) The generator complies with the following requirements:

(d)(5)(i) At all times there must be at least one employee either on the premises or on call (i.e., available to respond to an emergency by reaching the facility within a short period of time) with the responsibility for coordinating all emergency response measures specified in paragraph (d )(5)(iv) of this section. This employee is the emergency coordinator.

(d)(5)(ii) The generator must post the following information next to the telephone:

(d)(5)(ii)(A) The name and telephone number of the emergency coordinator;

(d)(5)(ii)(B) Location of fire extinguishers and spill control material, and, if present, fire alarm; and

(d)(5)(ii)(C) The telephone number of the fire department, unless the facility has a direct alarm.

(d)(5)(iii) The generator must ensure that all employees are thoroughly familiar with proper waste handling and emergency procedures, relevant to their responsibilities during normal facility operations and emergencies;

(d)(5)(iv) The emergency coordinator or his designee must respond to any emergencies that arise. The applicable responses are as follows:

(d)(5)(iv)(A) In the event of a fire, call the fire department or attempt to extinguish it using a fire extinguisher;

(d)(5)(iv)(B) In the event of a spill, contain the flow of hazardous waste to the extent possible, and as soon as is practicable, clean up the hazardous waste and any contaminated materials or soil;

(d)(5)(iv)(C) In the event of a fire, explosion, or other release which could threaten human health outside the facility or when the generator has knowledge that a spill has reached surface water, the generator must immediately notify the National Response Center (using their 24-hour toll free number 800/424-8802). The report must include the following information:

(1) The name, address, and U.S. EPA Identification Number of the generator;

(2) Date, time, and type of incident (e.g., spill or fire);

(3) Quantity and type of hazardous waste involved in the incident;

(4) Extent of injuries, if any; and

(5) Estimated quantity and disposition of recovered materials, if any.

(e) A generator who generates greater than 100 kilograms but less than 1000 kilograms of hazardous waste in a calendar month and who must transport his waste, or offer his waste for transportation, over a distance of 200 miles or more for off-site treatment, storage or disposal may accumulate hazardous waste on-site for 270 days or less without a permit or without having interim status provided that he complies with the requirements of paragraph (d) of this section.

Does anyone know what the regulatory citation is for signage for a 90 day area?  Usually, you see signage that says something like "Hazardous Waste Accumulation Area" then some other verbage which I've seen vary.  I can't find the citation.  This is for an episodic generator, not a TSDF.

Maria Race